Florida Republican state senators Rob Bradley, left, and Wilton Simpson confer during debate on the “stand-your-ground” bill Wednesday. (AP Photo/Steve Cannon)

The Florida Senate passed a measure this week that would strengthen the state’s so-called “stand-your-ground” law, shifting the burden of proof from defense attorneys to prosecutors in pretrial immunity hearings.

The controversial changes to the state’s self-defense law passed the Senate 23 to 15 along party lines. It was the subject of heated debate between proponents, who argued that it correctly forces prosecutors to prove why the law should not apply to a defendant, and opponents, who said it will effectively force two trials, doubling the workload and making it more difficult to get witnesses to testify.

The House is expected to vote on the measure next week, and Gov. Rick Scott (R) is expected to sign it. His office did not respond to a request for comment.

“If you exercise a God-given right, the right of self-defense, you don’t have the same rights as everybody else. You’re not innocent until proven guilty,” said Marion Hammer, a lobbyist with the National Rifle Association in Florida. “That’s wrong. That’s what needs to be fixed.”

The current Florida law allows residents to use force, including deadly force, if they “reasonably believe” that their lives are in danger or they risk bodily harm. The law says they have no duty to retreat. Defendants can claim immunity under the law but must provide evidence to prove their case. Under the bill passed this week, prosecutors would have to prove why a person should not be granted immunity from the crime. The law applies not only to shootings, but also to misdemeanors, domestic violence and assault cases that don’t involve guns.

The measure passed this week has been vehemently opposed by the state’s prosecutors, who said it will further strap an already strained system and deter witnesses in sensitive cases from testifying.

“This is an anti-law enforcement bill. It’s saying they don’t trust law enforcement either at the arresting stage or filing stage or state attorney, that we don’t understand a self-defense case,” said Phil Archer, the state attorney for Brevard and Seminole counties.

Archer, who said he is a member of the NRA and teaches self-defense, including stand your ground, said his office had four stand-your-ground cases last year. Should the bill pass, he expects the number to rise to”four thousand.” He said it would be malpractice for a defense attorney not to request an immunity hearing in any case in which self-defense is claimed, because the burden of proof would rest with the prosecution.

There will now be “two complete trials,” Archer said. “In every one of those cases, witnesses are going to have to take more time off work. Police officers who should be out on the street keeping us safe will now be in court, for what?”

Hammer said that if the authorities “do their job before they arrest and charge they’ll only have to do it once because the bad cases will get dismissed.”

The law is opposed by the Florida State Conference of NAACP Branches.

“Shifting the burden of proof to prosecutors increases the potential of denying justice to victims and their families. These laws are often applied in a racially biased manner, they do not deter crime, and the bottom line is that they make it easier for people to murder other human beings and not face any legal consequence,” said Adora Obi Nweze, the group’s president.

The state became the first in the nation to pass a stand-your-ground law in 2005; 34 states now have such legislation on the books, according to the American Bar Association. Florida’s self-defense laws came under scrutiny in 2012, when George Zimmerman shot and killed Trayvon Martin, an unarmed black teenager, in Sanford. Zimmerman’s attorney did not raise a stand-your-ground defense at trial. He was acquitted by a jury.

Gun-control groups are continuing to fight the measure, urging Floridians to call legislators and oppose the bill. Lucy McBath, whose 17-year-old son, Jordan Davis, was shot and killed in a Florida gas station parking lot for playing loud music, said the legislature has ignored “senseless killings” like those of Davis and Martin.

The law has returned to the spotlight in recent weeks during the trial of retired Tampa police captain Curtis Reeves, who shot a man at a movie theater in 2014 over a disagreement about a cellphone. A judge denied immunity to Reeves, who will now stand trial for murder.

Adam Winkler, a professor at the UCLA School of Law, said stand your ground has been a long-standing legal principle to justify the use of deadly force, but Florida’s measure would give special weight to defendants including, he argues, gun defendants.

“This new revised stand-your-ground law may really inhibit the proper functioning of the judicial system,” he said. “No other criminal defendant gets the benefit of a trial before a trial, a trial to see if they can go on trial.”