The DFL-led Minnesota Senate approved a measure legalizing gun silencers Thursday night, risking a showdown with Democratic Gov. Mark Dayton who just hours before sent legislators a letter threatening to veto the provision.

"Nowhere in the Second Amendment to the United States Constitution does it refer to the right to bear a silencer," Dayton wrote in the letter. "To allow gunshots to be silenced increases the danger to law enforcement officers, and to innocent bystanders."

Along with the silencer provision, the Senate approved a package of gun rights measures that match similar legislation that passed the House last week.

The silencer issue, which passed 40-23 with bipartisan support, is one that threatens to further divide the Senate and the governor, who issued his first written veto threat of the session over the matter. Already, more than 35 states permit gun silencers and others are considering it.

Gun rights advocates say silencers, also known as suppressors, reduce hearing problems related to loud gunfire and have unfairly gained a bad reputation from Hollywood movies that portray them as ideal tools for stealthy crimes.

Advocates say the devices do not silence but merely reduce gun noise by about 30 decibels; even the smallest firearms create noise of at least 140 decibels, according the American Speech-Language-Hearing Association.

Opponents of the silencers say the sound of gunfire assists police responding to calls and serves as a warning system for residents. They say gun owners worried about hearing loss should wear earplugs instead.

The veto threat came on a day when the Senate took up a range of criminal justice issues.

The full criminal justice measure, which passed 39-22 late Thursday, would restore voting rights to felons who are done with their imprisonment. The proposal would also seek to keep youths out of what is sometimes called the "cradle-to-prison pipeline" by establishing a diversion program for juvenile offenders. The measure would also prevent police from using drones without a search warrant, except in the case of certain emergencies.

The Senate also approved an amendment to spend $250,000 to find ways to prevent Minnesotans from joining terrorist groups like ISIL; a House panel approved $250,000 for the same purpose earlier this week.

Separately, a Senate committee attached a provision to a budget measure that would allow undocumented immigrants to earn driver's licenses.

The bulk of the discussion over the criminal justice bill, however, was consumed by the ability of felons to win back their voting rights.

A group of about 100 activists gathered outside the Senate chambers, chanting and praying to press for felon voting rights, driver's licenses for undocumented immigrants and juvenile justice changes. The group hopes the Senate action will create momentum for passage in the House or in final negotiations between the two bodies.

"We're here to have our voices heard so our dignity is respected, and we do that by standing together!" shouted the Rev. Paul Slack, president of Isaiah, an ecumenical group of about 100 churches, synagogues and mosques.

Brian Fullman, who came to the rally from Blaine, has been affected by all three issues, he said. As a young man, he became a felon for selling drugs before a boot camp prison diversion program changed his life, he said.

As manager of a barbershop in Brooklyn Park, Fullman said he's been educated about the immigrant experience by serving undocumented Liberian immigrants who want driver's licenses so they can work to support their families.

And, as a father, Fullman said, he struggled with a child in what he said was a failing juvenile justice system: "He needed to be broken down and built back up like I was, not warehoused, playing cards and eating sandwiches."

Not everyone agreed felons deserve voting rights.

"Let's pay attention to the victims and what they have suffered," said Sen. Warren Limmer, R-Maple Grove. "Individuals who have committed crimes and been convicted should receive a punishment when they victimize our innocent constituents."

Slack said the group's advocacy embodied the message of Scripture. "God is all about redemption, giving us another chance to correct our mistakes and live in dignity."

Patrick Coolican • 651-925-5042