Updated

A state Senate committee dismissed warnings from a Missouri doctor that nullifying federal gun laws would lead to greater firearms access and, consequently, more gun-related deaths and voted to advance such a measure Tuesday.

The Senate General Laws Committee voted 5-1 to adopt the bill that would allow federal agents to be prosecuted for enforcing gun control laws considered "infringements on the right to keep and bear arms." Agents found guilty could face up to a year in prison and a $1,000 fine.

Supporters at Tuesday's hearing said federal proposals to expand background checks and impose an assault weapons ban would unfairly punish gun owners. But Robert Flood, a pediatric doctor at St. Louis University and Cardinal Glennon Children's Hospital, said the bill is written under the mistaken concept that more guns lead to greater safety.

"Children are more likely to die by firearms in states with lax gun laws," he said. "Rather than being used for self-protection will be used on other people."

Courts have consistently ruled that states cannot nullify federal laws, but that hasn't stopped them from trying. Supporters of the gun legislation also pointed to the federal government's decision not to challenge new laws in Colorado and Washington allowing recreational use of marijuana as precedent for states to oppose Washington.

The GOP-led Legislature began pushing for comprehensive pro-gun legislation last year, but its attempt to nullify federal gun control laws failed after Republicans could not get enough votes to override Democratic Gov. Jay Nixon's veto.

Like last year's version, the legislation would also allow designated school personnel to carry concealed weapons in buildings. Another provision would let holders of concealed gun permits carry firearms openly, even in municipalities with ordinances banning open carry.

It would also lower the minimum age to get a concealed weapons permit to 19, down from 21. Flood said expanded access to concealed weapons for younger people posed a danger because adolescents are not as mentally developed as adults.

But the measure's sponsor questioned whether expanding access to teenagers would directly cause an increase in gun violence.

"We all know that teenagers are stupid. We are not arguing whether teenagers are stupid. We are debating whether putting a gun in their hands makes them go out and kill people," said the measure's sponsor Sen. Brian Nieves, R-Washington.

Sen. Jamilah Nasheed, D- St. Louis, cast the lone "no" vote. She said the Senate should focus more on legislation to address urban gun violence and not on bills that could increase weapons access.

Nieves' bill is less specific than last year's version about which federal laws it seeks to nullify. It removes references to the 1934 and 1968 gun control acts, while keeping generic references to fees, registration and tracking policies that "have a chilling effect on the purchase or ownership" of guns and ammunition by law-abiding citizens.

The measure now heads to the Senate floor, where the chamber's Republican leaders have dubbed the legislation a priority.