Colorado's new gun laws are “burdensome” and “a symbolic gesture that does not improve public safety,” a lawyer said on the first day of testimony of a trial that takes on the legislation passed last year.

But a state's attorney said that the laws do nothing to take away guns from law-abiding citizens and that the motivation behind the legislation is to curb mass shootings like the ones that occurred at Columbine High School and from inside an Aurora movie theater.

“In response to these events, Colorado's elected representatives made a policy decision to pass two pieces of legislation that appropriately balances the state's public safety concerns with the respect of the Second Amendment rights of citizens,” said Deputy Attorney General Matthew Grove.

The lawyers' arguments opened a two-week trial over a lawsuit filed against the state and Democratic Gov. John Hickenlooper that alleges that two recently enacted gun laws violate gun owners' Second Amendment right to bear arms.

At question are laws that expand background checks on gun sales in Colorado and limit the number of rounds that an ammunition magazine can hold to 15.

The lawsuit is being brought by gun rights groups and is being heard in a Denver U.S. District Court by Judge Marcia Kreiger.

A successful effort by the plaintiffs could put the new laws — which were signed by Hickenlooper last year — in jeopardy.

Debate on the bills last year caused highly-charged partisan rancor at the Capitol between Democrats who backed the efforts and Republicans who uniformly voted against them. The bills also led to last year's recall elections, where three Democratic lawmakers either lost or resigned their seats.

The new background checks law expands a previous statute that requires gun shops to conduct a criminal history prior to the sale of any firearm. The updated law expands that to all sales and transfers, regardless of where or how they occur.

Plaintiffs' attorney Richard Westfall argued that the new background checks law is unreasonable and unenforceable. He took particular issue with a part of the law that prohibits the transfer of guns among friends and family members, without having background checks conducted.

“There is no justification for such a burden, particularly because this statute doesn't even work,” Westfall said.

Westfall also took on the magazine limit ban, which bans new sales and transfers of high-capacity ammunition magazines. The law does not apply to existing magazines that may already be in a person's possession.

Westfall argued that the law is unenforceable because “tens of millions of magazines over 15 rounds exist.” He also said the Legislature was “moved by high-profile mass shootings” and that the laws are “a symbolic gesture that do not improve public safety.”

“The question is whether the magazine ban will have any positive impact on public safety at any level,” he said.

But Grove pushed back against those arguments. He contends that expanding background checks to all potential gun buyers “makes it more difficult for a prohibited person from acquiring firearms.”

In defending the new magazine limit, Grove said that restricting the number of rounds that a killer can hold limits the damage that he or she can inflict.

“Reloading creates a crucial window of opportunity for a victim to escape or to disarm a gunman,” Grove said.

And Grove said that the laws are not aimed at limiting the possession of guns by a law-abiding citizen.

“It does not take these items away from people who already own them. It does not restrict their lawful use. It does not limit the choices of firearms Coloradans can carry,” Grove said.