Legal Digest

Is It Truly an Emergency? Missouri v. McNeely and Warrantless Blood Draws

By Michael J. Bulzomi, J.D.
First responders and a police officer at the scene of an automobile accident.

Driving under the influence of alcohol can lead to many consequences, such as an encounter with law enforcement, an automobile accident, injury or loss of life, and suspension of driving privileges. This act impacts the life of the driver and possibly the lives of others, especially if an accident has occurred. 

In accident situations, compelling and competing interests arise. At the scene law enforcement officers respond to a chaotic situation in which time proves crucial. Glass and car parts litter the roadway. Emergency vehicles with flashing lights race to the injured so personnel can render aid. First responders must act effectively and efficiently because the scene must be cleared, injured persons require treatment and transportation, and officers need to collect evidence. Investigators must assess their need and ability to collect a blood sample to assess alcohol content.


Recently, the U.S. Supreme Court in Missouri v. McNeely addressed the Constitution’s requirement that all searches must be reasonable in the context of a nonconsensual warrantless blood-draw incident to support an arrest for driving under the influence.1 This article discusses that case and its practical impact and provides a historical overview of the authority of law enforcement officers to collect such evidence without a warrant.


While the Fourth Amendment generally mandates a warrant for searches, the U.S. Supreme Court has recognized a number of exceptions to this requirement. As one example, officers can conduct a warrantless search when confronted with emergencies or exigent circumstances.3 The Court has advised that “exigencies of the situation” may “make the needs of law enforcement so compelling that a warrantless search is objectively reasonable.”4 An example of an exigency is evanescent evidence, or evidence that is being destroyed. For instance, the Court has permitted warrantless searches to prevent the destruction of evidence when a suspect removed from under his fingernails a deceased victim’s tissue during an interview with police and, as relevant in the McNeely case, when a blood-alcohol content measurement became necessary. 

Special Agent Bulzomi is a legal instructor at the FBI Academy.
Special Agent Bulzomi is a legal instructor at the FBI Academy.

In Schmerber v. California, the Supreme Court held that the nonconsensual, warrantless seizure of blood for purposes of alcohol detection following what the officer reasonably concluded was an alcohol-related traffic accident was acceptable under the Fourth Amendment.5 Schmerber was involved in a car accident and later convicted of driving an automobile while under the influence of alcohol. The police officer who arrived at the scene of the accident reported smelling liquor on Schmerber’s breath. He also noted that Schmerber’s eyes had a glassy appearance and were watery and bloodshot. The officer accompanied Schmerber to the hospital that treated his injuries. Approximately 2 hours after arriving at the hospital, the same officer noticed that Schmerber still displayed symptoms of drunkenness and arrested him. Schmerber refused a breathalyzer test, so the officer directed a physician to draw a blood sample. The chemical analysis revealed a blood-alcohol level indicating intoxication. The lab results were admitted into evidence at trial. Schmerber objected to the evidence of the blood-alcohol analysis, arguing that it constituted an unreasonable search in violation of the Fourth Amendment. The U.S. Supreme Court rejected this argument.6

The Court determined that taking the blood sample was “plainly” a search and that such an intrusion into the human body ordinarily requires a warrant.7 But, the Court concluded that the officer’s decision to proceed without a warrant was acceptable under the circumstances based upon the government’s need for the blood sample, the relatively minor intrusion on Schmerber’s privacy interests, and the reasonable manner in which the test was conducted.8 The Court relied on the fact that the officer reasonably believed that he confronted an emergency in which the delay necessary to obtain a warrant under the circumstances threatened “the destruction of evidence.”9 This case required time to investigate the scene of the accident and then transport the suspect to a hospital, thus, infringing on any opportunity to take the time to prepare and present a warrant to a magistrate. Given these facts the Court concluded that securing evidence of blood-alcohol content without a warrant in this case was reasonable under the Fourth Amendment.10 The result in Schmerber led to a somewhat categorical approach to the warrantless removal of blood incident to what is believed to be an alcohol-related event, an approach that in light of the result in Missouri v. McNeely should be reassessed.


At approximately 2:08 am, a Missouri state patrol officer observed a truck driven by Tyler McNeely exceeding the posted speed limit and repeatedly crossing the center line. After stopping the vehicle, the officer noticed a strong smell of alcohol on McNeely’s breath, bloodshot eyes, and slurred speech. McNeely also admitted to having had a couple of beers and appeared unsteady on his feet, indicating intoxication. The officer’s suspicions were strengthened further by McNeely’s poor performance on the four field-sobriety tests administered. McNeely refused to take a preliminary breath test. He was arrested for driving under the influence and during transport declined a request to submit to a breathalyzer test at the police station. McNeely then was taken to a hospital for an evidentiary blood draw, which he would not consent to. Despite his refusal, a hospital laboratory technician took a sample approximately 23 minutes after the initial stop. The analysis showed a blood-alcohol concentration well above the legal limit. McNeely sought to have the blood analysis suppressed on the basis that the warrantless, nonconsensual blood draw violated his rights under the Fourth Amendment. The Missouri Supreme Court ruled that Schmerber “requires more than mere dissipation of blood-alcohol evidence to support a warrantless blood draw.”12

The U.S. Supreme Court agreed to hear this case to resolve a split of opinion among U.S. Circuit Courts of Appeals and state courts with respect to whether the dissipation of the evidence alone created exigent circumstances.13 In its holding the Court recognized that a limited number of warrant exceptions apply categorically. Categorical search warrant exceptions include search incident to arrest, the motor vehicle exception, and consent.14 However, the imminent destruction of evidence requires exigency-based considerations, determined by assessing the totality of the circumstances. The Court agreed with the state court, finding that the present case “involved a routine DWI investigation where no factors other than the natural dissipation of blood alcohol suggested that there was an emergency, and, thus, the nonconsensual warrantless test violated McNeely’s right to be free from unreasonable searches of his person.”15

According to the Court, the dissipation of the alcohol is merely one factor to consider in the totality of the circumstances when deciding whether an emergency exists. The Court noted that in Schmerber police were faced with an accident investigation and the need to transport the injured suspect to the hospital. No such special circumstances existed in McNeely.16


Many things have changed since 1966, including an understanding of the Schmerber decision and advancements in technology. Historically, the Schmerber decision was interpreted as having created a categorical exception for blood draws in driving-under-the-influence cases. McNeely clarified that such is not the case. In McNeely the Court noted that a totality-of-the-circumstances test was applied in Schmerber to determine the reasonableness of forgoing a search warrant when facing exigent circumstances and quickly dissipating evidence. In McNeely the Court reiterated that to determine the reasonableness of a warrantless search in the face of exigent circumstances, the test to apply is the totality of the circumstances, with the destructibility of the evidence as just one factor in the overall analysis.

The U.S. Supreme Court did not have the opportunity to determine all of the relevant factors in regard to the exigency of the situation in McNeely. The arresting officer testified in state court that he did not seek a warrant because “he believed that it was not legally necessary to obtain a warrant.”17 The Court did state that the metabolization of alcohol in the blood stream and the resulting loss of evidence are factors among others that should be considered in deciding the necessity of a warrant.18


“While the Fourth Amendment generally mandates a warrant for searches, the U.S. Supreme Court has recognized a number of exceptions to this requirement.”

In McNeely the Supreme Court mentioned several factors that may be considered in the totality-of-the-circumstances analysis. These include the time it would take to obtain a warrant, the impact of technological advancement in warrant acquisition, and the availability of a magistrate. 


Critical in whether exigent circumstances support a warrantless search is whether a warrant could have been obtained in a reasonable amount of time before evidence is lost. In Schmerber the Court determined that the officer’s actions were justified because “the delay necessary to obtain a warrant, under the circumstances, threatened the destruction of evidence,” in that “the percentage of alcohol in the blood begins to diminish shortly after drinking stops.”19 Time was of the essence due to the fact that there had been considerable delay in the investigation due to the complexities of handling an accident scene and the necessity to transport the suspect to the hospital for treatment. These complications were not present in McNeely.

The Court also recognized that the warrant process itself takes time. Inevitably time is consumed by police officers or prosecutors in completing the warrant application and by magistrate judges in reviewing the applications. However, the Court took note that the process has been streamlined to save time in many jurisdictions through the use of standard-form warrant applications to obtain blood-alcohol content in such investigations.20 The essential issue seems to be how much delay is introduced by getting a warrant and the resulting impact on the continued presence of the evidence.


Technological advancements over the decades since Schmerber was decided to have enabled law enforcement to secure warrants far more quickly than they previously could have.  The Court noted that in 1977 the Federal Rules of Criminal Procedure were amended, allowing federal magistrate judges the ability to issue warrants based on sworn testimony communicated by telephone.21 The rule was amended further to allow the use of “telephone or other electronic means.”22 The Court also commented on how a majority of states have implemented similar rule changes allowing law enforcement officers and prosecutors to apply remotely for warrants through telephonic or radio communication, e-mail, or video conferencing.23 The officer in Schmerber had none of these options. In McNeely the Court observed that technological advancements may provide an opportunity for officers to expeditiously obtain a warrant in such cases, minimizing the risk that the evidence would be lost, rendering a per se exception unnecessary.

Judicial Availability

“According to the Court, the dissipation of the alcohol is merely one factor to consider in the totality of the circumstances when deciding whether an emergency exists.”

The access to a judge also requires consideration. Even if one has the time and electronic means to communicate, a judicial officer still must be available. The Court stressed the essential role neutral magistrate judges play as a check on law enforcement discretion.24 However, no guarantee exists that a magistrate judge will be available at, for example, 2:08 am—the time of the traffic stop in McNeely. Not all jurisdictions provide around-the-clock magisterial coverage. Even those with night-duty judges confront availability issues in regard to dinner or coffee breaks and backlogs of prior warrant applications. Due to the evanescing nature of blood-draw evidence, a delay in communicating with a magistrate may render a warrantless blood draw reasonable.


The U.S. Supreme Court in McNeely rejected the idea that blood draws comprise part of a categorical exception to the Fourth Amendment search warrant requirement. The Court advised that a totality-of-the-circumstances test has been in place since Schmerber when considering exigency under the emergency search warrant exception. The Court noted “the context of blood testing is different in critical respects from other destruction-of-evidence cases in which police are truly confronted with a ‘now or never’ situation.”25 The natural dissipation of alcohol by the human body alone will not justify the finding of exigent circumstances. A decision to engage in a warrantless blood draw following an alcohol-related incident now must be supported by other factors in addition to the dissipation of the evidence, such as the inability to secure a warrant in a timely fashion.

“In McNeely the Supreme Court mentioned several factors that may be considered in the totality-of-the-circumstances analysis.”


1 569 U.S. ___ (2013), 133 S. Ct. 1552 (2013).

2 384 U.S. 757 (1966).

3 See Brigham City v. Stuart, 547 U.S. 398, 403 (2006); Cupp v. Murphy, 412 U.S. 291, 295 (1973); and Schmerber v. California, 384 U.S. 757 (1966).

4 Kentucky v. King, 131 S. Ct. at 1856 (quoting Mincey v. Arizona, 437 U.S. 385, 394 (1978)).

5 384 U.S. 757 (1966).

6 384 U.S. 757 at 758-772.

7 Id. at 767.

8 Id. at 767-772.

9 Id. at 771.

10 Id. at 772.

11 133 S. Ct. 1552 (2013).

12 Id. at 1558.

13 Compare 358 S.W.3d 65 (2012) (case below); State v. Johnson, 744 N.W.2d 340 (Iowa 2008) (same conclusion); and State v. Rodriguez, 2007 UT 15, 156 P.3d 771 (same) with State v. Shriner, 751 N.W.2d 538 (Minn.2008) (holding that the natural dissipation of blood-alcohol evidence alone constitutes a per seexigency); State v. Bohling, 173 Wis.2d 529, 494 N.W.2d 399 (1993) (same); and State v. Woolery, 116 Idaho 368, 775 P.2d 1210 (1989) (same).

14 United States v. Robinson, 414 U.S. 218 (1973). See California v. Acevedo, 500 U.S. 565 (1991); and Schneckloth v. Bustamonte, 412 U.S. 218, 219 (1973).

15 133 S.Ct. 1552, at 1555.

16 Id.

17 State v. McNeely, 358 S.W.3d 65 at 69 (2012).

18 133 S. Ct. 1552 at 1569.

19 384 U.S. 757 at 770-771.

20 133 S. Ct. 1552 at 1563; see 384 U.S. 757 (During the suppression hearing in this case, McNeely entered into evidence a search-warrant form used in drunk-driving cases by the prosecutor’s office in Cape Girardeau County, where the arrest took place. App. 61–69. The arresting officer acknowledged that he had used such forms in the past and that they were “readily available.” Id. at 41–42.)

21 Id.

22 Id.

23 See supra note 4 (state statute list).

24 Id. at 1562.

25 Id.; see also Roaden v. Kentucky, 413 U.S. 496, 505, 93 S.Ct. 2796, 37 L.Ed.2d 757 (1973).