– Minnesota’s hotly debated law that makes it a crime for suspected drunken drivers to refuse a breath test is facing its toughest test Wednesday as the U.S. Supreme Court weighs the constitutionality of the measure.

Two attorneys representing Dakota County will argue on behalf of Minnesota in State vs. Bernard, while D.C.-based attorney Charles Rothfeld will argue for William Bernard of Eagan.

Police approached Bernard at a public boat ramp in 2012 and asked him to consent to sobriety tests, saying he smelled of alcohol. Bernard declined the tests and was arrested, which led to felony charges for refusal to submit to chemical testing. Defense lawyers argue this law is a clear violation of the Fourth Amendment, which prohibits police from searching “persons, houses, papers and effects” unless there is a proper search warrant.

In the Bernard case, Minnesota’s state Court of Appeals upheld the state law that makes it a crime to refuse to take the test. But lawyers on the other side, including Dan Koewler, a Minnesota-based defense attorney, argue that punishing someone for refusing a blood, breath or urine test is unconstitutional.

“It does not make our roads any safer, it’s just a way to get easy convictions, and I’m expecting the Supreme Court to strike it down,” said Koewler, who is in D.C. for oral arguments Wednesday. “I don’t want drunken drivers on the roads. I just want the state to have a constitutional way of arresting and convicting people who are breaking these laws.”

Koewler’s firm was litigating this issue in front of the state’s Supreme Court back in 2009, when it ruled that drunken driving suspects could be criminally charged for refusing to consent to alcohol testing.

Some attorneys estimate that authorities administer 20,000 breath tests each year in Minnesota.

Last year, more than 100 Minnesota drivers had at least 10 driving while intoxicated convictions and almost 1,500 drivers had six or more DWI convictions, said the Minnesota Department of Public Safety.

In addition to Minnesota’s case, the court on Wednesday will hear two challenges out of North Dakota where it is also a crime to refuse a breath, blood or urine test — punishable to the same extent as a drunken driving conviction.

Attorneys argue it is inherently unconstitutional to be found sober while driving and face felony charges for refusing an alcohol test.

Only 13 states have implied-consent laws similar to Minnesota’s, though each state handles the laws somewhat differently. The justices are likely to steer clear of whether states have the ability to create the laws, but could try to furnish more clarity on enforcement due to the growing number of legal challenges in the states that have the laws, according to Law Street, a legal news website.

Duane Kokesch, program director for the National Traffic Law Center within the National District Attorneys Association, said he stands by the states with implied consent laws. He argues it cuts down on tense confrontations between police officers and suspected drunken drivers, giving police the ability to charge an uncooperative motorist with refusing to be tested.

“If someone is out there drinking alcohol, then they get in a car and they operate the car, the officer isn’t stopping someone for no reason, they are stopping them because they have probable cause,” said Kokesch, whose organization filed an amicus brief on behalf of the states in the case. “It’s treated separately, like obstructing justice or refusing to provide your name to an officer.”

Among the dozens of organizations that filed “friend of the court” briefs for this case is Mothers Against Drunk Driving, whose filing says 20 percent of drivers nationally refused to submit to a breath test.

Citing a study, MADD points out that refusing breath tests significantly cuts down on the likelihood an impaired driver will be convicted. In other words, states with high numbers of “refusal” rates had lower conviction rates for drinking and driving.