Democratic Rep. Dominick Moreno, who represents a district in suburban Denver, was among the four lawmakers. He said Biden "emphasized the importance of Colorado's role in shaping national policy around this issue."
Castle Rock Republican Rep. Carole Murray brought up Biden's calls during Monday's debate, saying she didn't appreciate "East-coast politicians" trying to influence Colorado legislators.
Democratic Gov. John Hickenlooper supports the expanded background checks, and thinks gun buyers should pay for them. He also said he may support limits on the size of magazines, if lawmakers agree to a number between 15 and 20. He said he hasn't decided whether to support banning concealed firearms on campuses and stadiums.
Republicans say students should have the right to defend themselves.
"Do not disarm our young adults in general and our young women in particular on our college campuses in the name of a gun-free zone," Republican Rep. Jim Wilson said.
The gun debate highlights a fundamental philosophical difference between many Democrats and Republicans.
"I resent the implication that unless we all arm ourselves we will not be adequately protected," said Dickey Lee Hullinghorst, the Democrats' leader in the House.
Republican Rep. Christ Holbert became emotional while explaining his opposition to the bills. He said he understood Fields cares about the bills, because of her district and because her son was shot and killed in 2005.
"But I care passionately about the United States Constitution and the constitution of this state, and the oath that we have taken," Holbert said.
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