Sarah A. Seo is an associate professor of law at the University of Iowa College of Law, where she teaches criminal procedure and legal history.

Justice Clarence Thomas stands ready to declare civil forfeiture unconstitutional. (Chip Somodevilla/Getty Images)

Last week, Attorney General Jeff Sessions rescinded restrictions that the Obama administration had placed on civil asset forfeiture, which allows law enforcement officials to seize property and cash that they believe are connected to criminal activity.

The Justice Department’s decision prompted a rare bipartisan outcry. Stories of individuals who had not been charged or convicted of any crime, yet have had to forfeit their cars, cash and even homes, have forged an unlikely alliance across the political spectrum. The ACLU and the libertarian Institute for Justice condemned the new policy. Sen. Mike Lee (R-Utah) and Rep. Justin Amash (R-Mich.) were among the conservatives who joined the chorus blasting the “big-government scheme to take people’s property without due process.”

But Sessions faces a bigger obstacle than bipartisan indignation. By reviving this practice, he has set himself up for a challenge before the Supreme Court, one in which he will have to contend with Justice Clarence Thomas — conservatives’ reliable ally, but now Sessions’s most formidable opponent.

This year, Thomas signaled that when the right case comes before the court, he would rule that the civil-forfeiture program is unconstitutional. When that happens, it will cut straight to a major ideological tension in conservatism today, presenting a showdown between law-and-order champions and small-government principles. It will also highlight “police exceptionalism,” an inconsistency on both sides of the political aisle between their beliefs about the exercise of state power and their favored approach to constitutional interpretation.

Thomas’s reasoning is based on an originalist interpretation of the Constitution, which, in a nutshell, maintains that the Constitution today means what it originally meant during the founding era. Civil forfeiture did exist in the 18th century, mostly to allow federal officials to enforce customs and revenue laws, which suggests the Founders believed that the practice was consistent with the Fourth Amendment.

Customs officials then, like narcotics agents today, could search ships and seize contraband without a warrant if they reasonably suspected that duties had not been paid. Necessity justified this exception to the warrant requirement. At any moment, ships could sail off into international waters and beyond U.S. jurisdiction.

But while Thomas would allow customs agents to continue searching ships and seizing contraband today, his originalism demands that civil asset forfeiture stop right there. In his view, modern-day civil asset forfeiture is unconstitutional because the forfeiture tool reaches far beyond the context of customs enforcement at the nation’s borders to drug-law enforcement anywhere within the country. It allows the seizure not only of the “instrumentalities of the crime” (the vessel used to transport the contraband) but also the “derivative proceeds of the crime” (the cash and even the goods bought with that cash).

Originalism did not justify the first major expansion of civil forfeiture. Instead, it was living constitutionalism, the liberal rival of originalism, that justified the compromise of due process rights by maintaining that constitutional meaning must evolve with the times. And this occurred not during the War on Drugs in the 1980s, but during Prohibition in the early years of mass-produced cars.

The automotive revolution was key to the expansion of both warrantless searches and civil forfeiture. Once the government outlawed alcohol sales, bootlegging became a booming business, one made possible by the modern motorcar. Drys — the faction that supported the ban — argued that obtaining a warrant for a moving target was impossible and that requiring one would thwart the ability to enforce Prohibition.

So state and federal governments expanded state power in two ways. Legislatures passed forfeiture laws allowing the warrantless seizure of cars and liquor. And to provide opportunities to seize the illicit goods, courts created the “automobile exception” to the Fourth Amendment to permit warrantless car stops. Prohibition’s legacy endures today as warrantless traffic stops provide the setting for many civil asset forfeitures.

Even in the era of bootleggers and speakeasies, not everyone bought the exigent-circumstances argument.

In a 1925 Mississippi case, a state judge pointed out that the police had plenty of time to get a warrant, arguing that the automobile aided not only criminals but also law enforcement. And even if cars sped up the criminal getaway, other technologies, such as the telephone and wireless radio, made it easy to contact officials in other jurisdictions to pursue the fleeing suspect.

In short, motor-powered vehicles may have transformed criminal investigations, but not enough to justify exceptions to established constitutional rights.

But this was the minority view. Since then, the mobility of cars has become an unquestioned rationale for warrantless police action, to the point that even when a car is immobilized, such as when it is towed to an impound lot, the police do not need a warrant to search it.

This brings us to the tension underlying the conflict between the priorities of the nation’s chief law enforcement officer and the Supreme Court’s most doctrinally conservative jurist, as well as broader contradictions between conservative-liberal politics and their preferred constitutional interpretations.

Conservatives, who usually embrace originalist arguments, typically prioritize law-and-order policies. Meanwhile, liberals, who usually prioritize the rights of criminal defendants, typically reject originalism in favor of living constitutionalism. For both sides, when it comes to civil asset forfeiture — and the police’s power more generally — their preferred method of interpreting the Constitution contradicts their usual policy preferences. Few judges and politicians are as consistent about applying their philosophy as Justice Thomas.

What explains these inconsistencies is that originalism almost always supports smaller government because state powers have only grown since the 18th century, while living constitutionalism normally justifies more state regulation. And because the police are part of the state, an interpretation of the Constitution that freezes law enforcement authority at the level that existed during the founding era would severely hamper what the police can do today — a doctrinal obstacle to the law-and-order policies favored by conservatives.

Although law-and-order proponents will have to abandon the purest forms of originalism to defend civil asset forfeiture, technological advances may soon offer liberals a way to align their position with living constitutionalism.

A few state courts have begun to examine the implications of smartphones and video-communication apps such as Skype or FaceTime, which make it possible for police officers to contact a judge to request a warrant remotely and almost instantaneously. Last month, the Iowa Supreme Court considered abandoning the automobile exception, but decided that the technology had not quite advanced to the point of eliminating automotive exigency.

But it is only a matter of time.

And the abolishment of warrantless car stops and searches can help to eliminate the situations that are most vulnerable to the abuses of civil asset forfeiture. When courts eventually decide that exigent circumstances no longer exist in a world of instant mobile communication, modern technology will have supported a return to founding-era limits on the police’s power.