Minnesota lawmakers must decide whether something less definitive than a search warrant would be just as effective at protecting citizen's constitutional rights.

The House is debating a move to regulate the use of controversial "cellular exploitation devices," which mimic local phone towers to capture the location of cellphones — and the suspects who carry them.

Companion bills in the House and Senate would require police to show probable cause and get a judge's signoff before deploying the devices. But the legislation has been stripped of all references to "search warrant," replacing them with "court order" and "tracking warrant." The move troubles civil liberties advocates who say the new language could render the laws toothless.

"Our concern is that a court order is not as defined as a search warrant," said Benjamin Feist, legislative director for the American Civil Liberties Union of Minnesota. "Minnesota law lays out all the protections that a search warrant specifically provides, but a court order is really unclear."

Chief Deputy Hennepin County Attorney David Brown, who lobbied for the changes along with the Minnesota Bureau of Criminal Apprehension and other agencies, said law enforcement is supportive of a higher threshold. But Minnesota's search warrant language is limited to searches of specific places and times, making it difficult for police to track across jurisdictional boundaries. Brown said law enforcement came up with the term "tracking warrant" to appease lawmakers' discomfort and to discern from court orders, which do not require probable cause — the current standard for using the devices. As long as "search warrant" is eliminated, whichever title is used will be backed by law enforcement, Brown said.

"We will leave it to the Legislature to come up with the appropriate labels for this," Brown said. "I don't think we have a great deal of concern whether it's one or the other once everyone agrees it's a written order based on probable cause."

It's the latest controversy surrounding the devices, commonly known as the Kingfish and Stingray, which were largely unknown to lawmakers until longtime privacy advocate Rich Neumeister obtained information about them under the Minnesota Data Practices Act. That information pushed lawmakers to demand answers and draft the legislation, which limits the length of time law enforcement may track suspects and requires them to note whom they've tracked. Warrants would not apply in some emergencies such as threat of imminent harm or death.

The Senate version passed 56-1 last week. Should it pass on Tuesday, the bill heads for conference committee, where the final language will be drafted.

Standard of review is key

Supreme courts in Massachusetts and New Jersey have ruled that a warrant is required to obtain cellphone location information. In 2012 the U.S. Supreme Court ruled 5-4 that installing a GPS on a vehicle to track a suspect constituted a search entitled to protections under the Fourth Amendment. However, tracking suspects through their phones without physically encountering their property is a different situation, said Scott Swanson, director of academic achievement for the University of St. Thomas School of Law.

"It's not really clear when it's a tracking device that's already there based on information that you give to a third party, and when you have a smartphone you are knowingly giving personal information to the cellphone company — in this case, where you are," Swanson said.

DFL Rep. Joe Atkins, who sponsored the House legislation, said that although the term "search warrant" was pulled from the bill, it's still strong legislation that addresses the privacy concerns of Minnesotans.

"For me the issue all along has been the standard of review," said Atkins, an attorney from Inver Grove Heights. "You could call it a zebra, or make up a word and call it a widget or a wiggle. For me all that matters are that judges are going to look at the standard of review that needs to be applied."

The sentiment was echoed by Sen. Branden Petersen, R-Andover, who said they changed the language "in the interest of moving the bill forward" but said it still holds law enforcement accountable.

Dissatisfaction with the change spanned both parties in the committees who heard the House bill when the language was amended. Rep. Peggy Scott, R-Andover, said in the House Judiciary Finance and Policy committee last month that she was uncomfortable with removing the term search warrant, which is what she considered "the meat of the bill." However, she said last week that because of its other strong notifications provisions, it will likely receive her vote.

"I'm disappointed that it seemed like we were settling for a lower bar, but this place is all about compromise," she said. "Sometimes you have to take the good with the bad and the good with the mediocre."

Abby Simons • 651-925-5043