by Max Baumbach*

When a motorist is arrested on suspicion of intoxicated driving, the government cannot compel him to submit to a blood draw without a warrant or warrant exception, nor can it make his refusal to submit to a blood draw a crime. But can the government use the refusal as evidence of guilt in a subsequent DUI prosecution on the basis of an implied consent statute? In this Contribution, Max Baumbach (’21) argues that the Fourth Amendment prohibits the use of blood test refusal evidence in a DUI prosecution where the test itself would have been unlawful to conduct in the first instance.


The Fourth Amendment guarantees that “[t]he right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated . . . .”2 The general rule established by the Supreme Court is that searches conducted without judicial warrants are per se unlawful, “subject only to a few specifically established and well-delineated exceptions.”3

All U.S. states have passed implied consent statutes dictating that motorists, by virtue of driving on public roads, have consented to chemical testing to determine their blood-alcohol level (“BAC”).4 Nevertheless, chemical tests of breath, blood, or urine are searches subject to the constraints of the Fourth Amendment.5 A state’s authority to punish drivers who reject testing is thus subject to limitations. In Birchfield v. North Dakota, the Supreme Court held that a motorist cannot be deemed to have consented to a blood draw “on pain of committing a criminal offense.”6

It is less clear, however, whether states may introduce a person’s refusal to submit to a warrantless blood test as evidence of guilt in a prosecution for driving under the influence (“DUI”). In Commonwealth v. Bell, the Supreme Court of Pennsylvania held that such refusal evidence was admissible, and the United States Supreme Court denied certiorari.7 The Pennsylvania court reasoned that the state’s implied consent statute differentiated Bell from other cases in which it had held that refusing a warrantless search cannot be admitted as evidence of guilt in a subsequent criminal prosecution.8

The doctrine endorsed in Bell and by other state courts9 would have significant ramifications for civil liberties if formally endorsed by the Supreme Court. This is especially apparent when viewed against the backdrop of rampant racial profiling on our nation’s roads and highways.10 Consider a scenario in which police stop a motorist of color for a minor traffic offense, incorrectly deem him to be intoxicated, and arrest him. The Bell rule allows the state to command the motorist to submit to an unnecessary blood draw and later prosecute him solely on the basis of his innocently motivated refusal. Because the rule is a blanket rule permitting all refusal evidence in DUI prosecutions, the state would be allowed to do this even if administering a blood draw would have been unconstitutional.

In light of the Court’s reasoning in Birchfield, as well as its other decisions regarding the legality of warrantless blood draws, this Contribution argues that without a search warrant or warrant-requirement exception, the Fourth Amendment prohibits a state from admitting a motorist’s refusal to submit to a blood draw as evidence of guilt in a DUI prosecution.

* * * * *

All standard forms of BAC testing are searches within the meaning of the Fourth Amendment.11 However, unlike breath tests, which may be freely administered without warrants as searches incident to arrest, blood draws are subject to no categorical warrant requirement exceptions.12 Three principal justifications exist for this distinction. The first is a normative justification: a blood draw is an extremely invasive procedure. It entails a “compelled surgical intrusion beneath [a motorist’s] skin and into his veins . . . .”13 The second justification, closely related to the first, is that an individual has a possessory interest in his own blood, such that drawing blood amounts to “extract[ing] a part of the subject’s body.”14 The third justification is that blood samples can be stored for extended periods of time and contain much more information about a motorist than just his BAC, creating additional privacy concerns.15

Because one’s BAC level dissipates with the passage of time, a warrantless blood draw may be justified by fact-specific exigent circumstances. For example, where delays associated with hospitalizing an injured motorist make it impractical to obtain a warrant, the state may draw the person’s blood without judicial approval.16 Similarly, a warrantless blood test is usually permissible when a motorist is unconscious, as breath tests require the subject to actively participate by blowing into a tube.17 However, the natural dissipation of alcohol from the motorist’s blood does not, in itself, justify a warrantless blood draw.18 Furthermore, the reasonableness of a blood test “must be judged in light of the availability of the less invasive alternative of a breath test.”19

Despite the Bell court’s reliance on implied consent statutes to differentiate BAC tests from other searches, these statutes do not provide an independent exception to the warrant requirement. Though the Supreme Court has spoken approvingly of the general concept of implied consent laws, its decisions “have not rested on the idea that these laws do what their popular name might seem to suggest—that is, create actual consent to all the searches they authorize.”20 The fact that the Supreme Court in Missouri v. McNeely found the BAC test at issue unlawful—even though the state had an implied consent statute—confirms that these statutes do not create actual consent to chemical testing.21 Multiple state courts have reached the same conclusion.22 Were it true that motorists could be deemed to have actually consented to chemical testing via statute, McNeely and Birchfield could have been resolved on grounds that the petitioners had consented solely by driving. Instead, Birchfield held that consent to searches must be “determined from the totality of the circumstances” and cannot be imputed by legislative fiat.23

The cumulative effect of these rules is that the government is rarely authorized to compel a warrantless blood draw from a motorist. Consider again the scenario in which a motorist has been arrested on suspicion of drunk driving after a pretextual traffic stop. The officer then demands a blood draw, despite the fact that the motorist is physically capable of performing a breath test and that there is ample time to administer a breath test. Notwithstanding any implied consent statute, if the motorist refuses to consent to a blood draw, the putative blood draw would constitute an illegal search if administered, and the officer would need to obtain a warrant for the blood draw or settle for a breath test.

* * * * *

The principle that the government may not “impose a penalty upon those who exercise a right guaranteed by the Constitution”24 has substantial legs in the Supreme Court’s jurisprudence. For example, in the Fifth Amendment context, a defendant’s silence may not be used as evidence of his guilt in a criminal prosecution.25 Nor may his silence be used to impeach an explanation subsequently offered at trial.26

Circuit courts have extended this rationale to the Fourth Amendment context and have “unanimously held that a defendant’s refusal to consent to a warrantless search may not be presented as evidence of guilt.”27 The high courts of several states have also adopted this rationale.28 In sum, nearly all jurisdictions prohibit the use of one’s refusal to consent to an otherwise unreasonable search as evidence of guilt.

The Supreme Court has held that the purpose of the Fourth Amendment is to “safeguard the privacy and security of individuals against arbitrary invasions by government officials.”29 As the majority of state and federal jurisdictions have recognized, the notion that one has a right to be free from “arbitrary invasions” necessarily means that refusing certain searches is “privileged conduct” deserving of protection.30 Contrary to the reasoning behind the Bell rule, these principles are no less applicable to the blood test refusals in the DUI context. In the first instance, there are many “personal reasons” why an individual might reject such a test, just as one “would not wish to have the police searching through their room.”31 The motorist, for example, could simply be afraid of needles. But, if the motorist’s refusal, however innocently motivated, were permitted to form the basis of a criminal prosecution for DUI, the right to refuse would be eviscerated and the authority of the government to draw his blood would be self-justifying.32

* * * * *

The high courts of Pennsylvania, Vermont, and Colorado have held that the United States Supreme Court has already approved laws that permit the admission of refusal evidence in DUI prosecutions. Pennsylvania arrived at this conclusion largely on the basis of a single passage in Birchfield:

Our prior opinions have referred approvingly to the general concept of implied-consent laws that impose . . . evidentiary consequences on motorists who refuse to comply . . . . Petitioners do not question the constitutionality of those laws, and nothing we say here should be read to cast doubt on them.33

The Bell court erred in interpreting this language in Birchfield as a full-throated endorsement of refusal evidence in DUI investigations. Firstly, none of the petitioners in Birchfield had their refusals used against them as evidence of guilt, thus they had no reason to raise the issue. It is therefore logical to read the Court’s “general approval” of test refusal evidence as dicta declining to address the issue at all.

More importantly, concluding that Birchfield greenlit evidentiary consequences for refusing BAC tests ignores the reasoning upon which that decision was based. As discussed by Judge Wecht’s dissent in Bell, the Court’s “heuristic for resolving the constitutional question upon which it granted certiorari [is] ‘that the criminal law ordinarily may not compel a motorist to submit to the taking of a blood sample or to a breath test’ without a warrant unless ‘such warrantless searches comport with the Fourth Amendment.’”34 Thus, the proper inquiry to apply when determining whether a refusal may be penalized is whether the government had the authority to conduct the refused search, not whether the penalty for refusal is sufficiently lenient to justify its imposition. Lower federal courts have consistently applied this inquiry as well.35

According to Professor Wayne LaFave,

[w]hat the cases indicate is that when defendant’s refusal was within the context of a recognized search-warrant-required category, then the Fourth Amendment prohibits admission of that refusal into evidence . . . . But on the other hand, when it is first determined that no warrant was required in any event (e.g., taking a breath sample), comment on the refusal is permissible.36

This heuristic neatly explains Birchfield’s first two dispositions: the blood draw that petitioner Birchfield refused was otherwise unlawful, thus he could not be penalized for refusing it; and the breath test that petitioner Bernard refused was a lawful search incident to arrest, thus he could be penalized because he “had no right to refuse it.”37

The Bell court also based its ruling on the Supreme Court’s decision in South Dakota v. Neville, which held that evidentiary penalties for BAC test refusal comport with the Fifth Amendment because the refusal is not compelled self-incrimination.38 Such reliance on Neville is misplaced. Neville did not hold that a state may penalize a motorist’s exercise of their Fifth Amendment right by allowing refusal evidence; it held that the motorist does not have a Fifth Amendment right to refuse BAC testing.39 That a motorist has a Fourth Amendment right to refuse a warrantless, exceptionless blood draw has been unassailably established by case law.40 It is notable that the opinion in Neville, a case decided in 1983, operated on the assumption that motorists lack any constitutional right to refuse blood tests in light of Schmerber v. California.41 This interpretation of Schmerber has since been discredited by the Court’s decision in McNeely, which read Schmerber to be a fact-specific decision finding that the particular blood draw in question was justified by exigent circumstances.42

* * * * *

Birchfield held that there “must be a limit to the consequences to which motorists may be deemed to have consented by virtue of a decision to drive on public roads.”43 Without precisely delineating the outer bounds of this limit, the Court insisted that “imposing criminal penalties on the refusal to submit to [a blood draw]” crosses the line.44

Even if one concedes that a state may impose certain penalties upon refusal to submit to otherwise unlawful testing, rules permitting the use of refusal evidence to prosecute motorists for DUI also cross the Birchfield line. The Vermont Supreme Court underestimates the acute danger accompanying such license when it says that “merely allowing evidence of the refusal at a criminal DUI trial, where a defendant can explain the basis for the refusal and the jury can consider the defendant’s explanation for doing so” is “qualitatively different” from making the refusal a standalone crime.45 The Supreme Court could have applied the same reasoning to a scenario where a defendant’s Fifth Amendment silence is permitted to be used as evidence of his guilt. It did not do so in Griffin v. California, because it realized that allowing such a penalty “cuts down on the privilege by making its assertion costly.”46 So, too, with refusals to consent to searches.

The Colorado Supreme Court has hung its hat on an assertion that the Birchfield court “has all but said that anything short of criminalizing refusal does not impermissibly burden or penalize a defendant’s Fourth Amendment right to be free from an unreasonable warrantless search.”47 This assertion lacks foundation. The Court in Birchfield stated that “motorists cannot be deemed to have consented to submit to a blood test on pain of committing a criminal offense.”48 That is precisely what has happened when a motorist is convicted for drunk driving based solely or partially on the exercise of his Fourth Amendment right to refuse an unreasonable blood draw. To say that evidentiary penalties for blood draw refusal survive Birchfield as long as they do not make refusal a standalone crime is to read language into the text that is not present, and to pose a distinction without a difference.

* * * * *

When a motorist refuses a warrantless blood draw justified neither by exigent circumstances nor any other warrant exception, he has properly exercised his Fourth Amendment right to be free from an unreasonable search. He therefore cannot be prosecuted on the basis of his refusal because the state lacks the authority to compel the test.49 This remains so whether refusal is made its own crime or is employed by the prosecution to impute guilt in an underlying offense, because holding a motorist’s refusal against him as evidence of guilt places “an unfair and impermissible burden” on his privileged conduct, in direct contravention of his Fourth Amendment rights.50


* Max Baumbach is a J.D. Candidate (2021) at New York University School of Law. This piece is a commentary on a problem produced for the 2020 Herbert Wechsler National Criminal Law Moot Court Competition, hosted by the University at Buffalo School of Law. The question presented was whether a motorist’s assertion of his Fourth Amendment right to refuse consent to a warrantless blood draw may be used as evidence of guilt for the offense of driving under the influence, or any related offense that flows from a DUI finding. The views expressed in this contribution do not necessarily represent the views of the author. The article is a distillation of one side of the argument assigned to the team.

2. U.S. Const. amend. IV.

3. Mincey v. Arizona, 437 U.S. 385, 390 (1978) (quoting Katz v. United States, 389 U.S. 347 at 357 (1967)).

4. See Nat’l Highway Traffic Safety Admin., Dep’t of Transp., Alcohol and highway safety:  A Review of the State of Knowledge 165, tbl. 5-6, 173 (2011).

5. Skinner v. Ry. Labor Exec. Ass’n, 489 U.S. 602, 617 (1989)

6. Birchfield v. North Dakota, 136 S. Ct. 2160, 2186 (2016).

7. Commonwealth v. Bell, 211 A.3d 761, 776 (Pa. 2019), cert. denied sub nom. Bell v. Pennsylvania, 140 S. Ct. 934 (2020).

8. Bell, 211 A.3d at 773; see also Commonwealth v. Welch, 535 A.2d 517 (Pa. 1991) (holding that refusing to consent to a search cannot be used as evidence of guilt outside the DUI context).

9. See, e.g., State v. Rajda, 196 A.3d 1108, 1111 (Vt. 2018) (holding that refusing a warrantless, exceptionless blood draw may be admitted as evidence of guilt in a DUI prosecution); accord Fitzgerald v. People, 394 P.3d 671, 676 (Colo. 2017).

10. See David A. Harris, Driving While Black: Racial Profiling On Our Nation’s Highways, American Civil Liberties Union (1999), https://www.aclu.org/report/driving-while-black-racial-profiling-our-nations-highways (last visited Aug. 14, 2020).

11. See Skinner, 489 U.S. at 617.

12. See Missouri v. McNeely, 569 U.S. 141, 159 (2013) (holding that motorists’ diminished expectation of privacy in automobiles does not apply to blood draws); Birchfield, 136 S. Ct. at 2185 (holding that breath tests, but not blood draws, can be justified as searches incident to arrest).

13. McNeely, 569 U.S. at 148.

14. Birchfield, 136 S. Ct. at 2164.

15. Id.

16. See Schmerber v. California, 384 U.S. 757, 770–71 (1966).

17. See Mitchell v. Wisconsin, 139 S. Ct. 2525, 2538 (2019).

18. See McNeely, 569 U.S. at 165 (rejecting a per se exigency exception for blood tests in DUI investigations).

19. Birchfield, 136 S. Ct. at 2184.

20. Mitchell, 139 S. Ct. at 2533.

21. See McNeely, 569 U.S. at 147.

22. See, e.g., Commonwealth v. Myers, 164 A.3d 1162, 1180 (Pa. 2017) (holding that the state’s implied consent statute “does not constitute an independent exception to the warrant requirement”); Williams v. State, 771 S.E.2d 373, 377 (Ga. 2015) (“[M]ere compliance with statutory implied consent requirements does not, per se, equate to actual, and therefore voluntary, consent . . . .”); Aviles v. State, 443 S.W.3d 291, 294 (Tex. App. 2014), remanded in light of McNeely from Aviles v. Texas, 571 U.S. 1119 (2014) (holding that implied consent statutes “[are] not substitutes for a warrant or legal exceptions to the Fourth Amendment warrant requirement”).

23. See Birchfield, 136 S. Ct. at 2186 (quoting Schneckloth v. Bustamonte, 412 U.S. 218, 227 (1973)).

24. Harman v. Forssenius, 380 U.S. 528, 540 (1965) (citing Frost & Frost Trucking Co. v. Railroad Comm’n of California, 271 U.S. 583 (1926)).

25. Griffin v. California, 380 U.S. 609, 615 (1965).

26. Doyle v. Ohio, 426 U.S. 610, 618 (1976).

27. United States v. Runyan, 290 F.3d 223, 249 (5th Cir. 2002); accord United States v. Dozal, 173 F.2d 787, 794 (10th Cir. 1999); United States v. Thame, 846 F.2d 200, 206–07 (3d Cir. 1988); United States v. Taxe, 540 F.2d 961, 969 (9th Cir. 1976).

28. See, e.g., State v. Banks, 434 P.3d 361, 348 (Or. 2019) (holding that “a person’s verbal refusal to consent to a warrantless search [cannot] be admitted as evidence of guilt”); accord Commonwealth v. Chapman, 136 A.3d 126, 131 (Pa. 2016); State v. Jones, 753 N.W.2d 677, 687 (Minn. 2008); Longshore v. State, 924 A.2d 1129, 1159 (Md. 2007); State v. Palenkas, 933 P.3d 1269, 1280 (Ariz. 1996); Garcia v. State, 712 P.2d 1375, 1376 (N.M. 1986); Elson v. State, 659 P.2d 1195, 1199 (Alaska 1983).

29. Camara v. Mun. Ct. of City & Cty. of San Francisco, 387 U.S. 523, 528 (1967).

30. United States v. Prescott, 581 F.2d 1343, 1353 (9th Cir. 1978).

31. Commonwealth v. Welch, 535 A.2d 517, 520 (Pa. 1991); see also United States v. Clariot, 655 F.3d 550, 555 (6th Cir. 2011) (describing evidentiary value of search refusal as “de minimis”); United States v. Moreno, 233 F.3d 937, 941 (7th Cir. 2000) (the same).

32. See Bargas v. State, 489 P.2d 130, 132 (Alaska 1971) (“It would make meaningless the constitutional protection against unreasonable searches . . . if the exercise of that right were allowed to become a badge of guilt.”).

33. Bell, 211 A.3d at 775–76 (quoting Birchfield, 136 S. Ct. at 2185).

34. Bell, 211 A.3d at 782 (Wecht, J., dissenting) (quoting Birchfield, 136 S. Ct. at 2172).

35. Compare United States v. Phillips, Nos. 91-10478, 91-10479, 1992 WL 231124, at *3 (9th Cir. Sep. 21, 1992) (holding that motorist had Fourth Amendment right to refuse blood draw, thus refusal evidence was inadmissible), with United States v. Rapanos, 115 F.3d 367, 373–74 (6th Cir. 1997) (holding that defendant had no right to refuse visual inspection of open field, thus refusal evidence was admissible).

36. 4 Wayne R. LaFave & David C. Baum, Search & Seizure § 8.2(l), at 27 (5th ed. Supp. 2018).

37. Birchfield, 136 S. Ct. at 2165.

38. Bell, 211 A.3d at 776 (citing South Dakota v. Neville, 459 U.S. 553, 560 (1983)).

39. Neville, 459 U.S. at 563 (holding that “the values behind the Fifth Amendment are not hindered when the state offers a suspect the choice of submitting to the blood-alcohol test or having his refusal used against him.”).

40. See Birchfield, 136 S. Ct. at 2186 (describing North Dakota’s assumption that states can compel warrantless blood draws as “erroneous”).

41. Neville, 459 U.S. at 559 (citing Schmerber, 384 U.S. at 765) (“Schmerber, then, clearly allows a State to force a person suspected of driving while intoxicated to submit to a blood alcohol test.”).

42. McNeely, 569 U.S. at 156.

43. Birchfield, 136 S. Ct. at 2185.

44. Id. at 2185–86.

45. Rajda, 196 A.3d at 1120.

46. Griffin v. California, 380 U.S. 609, 614 (1965).

47. Fitzgerald v. People, 394 P.3d 671, 676 (Colo. 2017).

48. Birchfield, 136 S. Ct. at 2186 (emphasis added).

49. Id. at 2186.

50. United States v. Prescott, 581 F.2d 1343, 1351 (9th Cir. 1978).