Michigan Gov. Rick Snyder (R) has vetoed a bill that would have allow concealed weapons in schools, day care centers, sports arenas, bars, places of worship, hospitals, dorms and casinos.

“While we must vigilantly protect the rights of law-abiding firearm owners, we also must ensure the right of designated public entities to exercise their best discretion in matters of safety and security,” he said in a letter sent to the legislature. “These public venues need clear legal authority to ban firearms on their premises if they see fit to do so.”

The bill's sponsor, state Sen. Mike Green (R), told the Detroit News that Snyder wanted language that would allow public schools to ban concealed weapons. He refused, fearing it could be used to overturn a law that prohibits local firearms laws from trumping state laws. 

"They told us Thursday night he'd veto it if we didn't include that language," Green told the paper. "We just said 'enough's enough' and we passed it."

In a statement following the veto, Green said he was "deeply disappointed" in Snyder's decision. "The message being sent to law-abiding folks with a license now is that if you wish to protect yourselves and your families from tragedy in these areas, you’ll have to carry openly without additional training," he said.

The bill would have banned anyone with a concealed-carry license from carrying a gun openly in gun-free zones, as is currently allowed (with exceptions). Gun owners would need additional training to carry concealed weapons in these areas. 

Snyder told reporters earlier in the week that he would give the bill extra scrutiny due to the questions raised by the massacre in Newtown, Conn. The Michigan governor was recently in the national spotlight for signing controversial legislation banning unions from requiring workers to pay membership dues. 

Other governors have expressed new interest in bringing guns into schools in response to the Newtown deaths. Virginia Gov. Bob McDonnell (R) said there " should at least be a discussion" of arming school principals. Texas Gov. Rick Perry (R) said it should be up to local school districts, but that someone with a concealed-carry license "should be able to carry a gun anywhere in the state."