A bid to change state law to require background checks at gun shows, CBS News Correspondent Bob McNamara reports that Amendment 22's journey to the ballot has been a long and controversial one.
It has survived a half-dozen legal challenges by gun groups. It is the target of a $600,000 National Rifle Association campaign. It has earned the support of the White House and Arizona Sen. John McCain.
And even if voters approve it, as expected, opponents promise more court battles to come. For Tom Mauser, the amendment's chief architect, that means the crusade will continue.
Mauser's son Daniel was murdered at Columbine, one of 13 people slain on April 20, 1999, by two students armed with firearms purchased at a gun show.
"His words to me two weeks before he was killed, 'Dad, did you know there are loopholes in the Brady Bill?'" Mauser recalls. "Those words are what have motivated me to carry out his wish to close that loophole."
While Colorado requires criminal background checks of those who buy guns from government-licensed retail arms-dealers, at gun shows, only people buying guns from federally licensed gun dealers have to undergo criminal background checks. Sales by private dealers are exempted. The initiative would require background checks for all sales at gun shows.
Mauser's amendment even has the support of the woman who unwittingly bought three of the four guns the Columbine killers used.
"It was entirely too easy to purchase the guns and I honestly believe something should be done," said Robyn Anderson.
For gun owners, however, the issue at the heart of Amendment 22 is freedom.
"This is the first step towards confiscation," said Dudley Brown of Rocky Mountain Gun Owners. "And that's what we're fighting here."
Dealer Mel Bernstein agrees. Squeezing off a few rounds from an M60 machine gun, he tells a reporter, "That's freedom, man. That's all part of being in America."
Bernstein also feels that the truth of the matter is there will always be loopholes.
"They'll just buy 'em through the newspaper, go citizen to citizen," he predicts. "There's always a way for criminals to get guns. They're always gonna get guns."
Amendment 22 mandates background checks at all gun shows, which are defined as events where more than 25 guns are sold. It exempts sales of antique guns or relics. It also requires licensed dealers to keep records of gun sales, and imposes jail time and fines for vioations.
Colorado's Supreme Court ruled in early October Amendment 22 could go on the ballot, rejecting a challenge by gun rights advocates who said the measure should not go on the ballot because signatures were gathered before the Court approved the wording.
But the high court said signatures were valid because they were collected after a state board approved the wording.
Strengthening the system of background checks has been a focus of recent gun control efforts outside of Colorado. President Clinton last month announced that the Treasury Department and its Bureau of Alcohol, Tobacco and Firearms were setting up a Web site called "eZ Check" to allow licensed gun dealers to quickly verify the validity of licenses presented to them for purchase or shipment of guns.
Efforts at gun control in the wake of Columbine have faced an uphill battle. In February, the state legislature killed several gun control measures inspired by the massacre.
According to the Rocky Mountain News, the legislature passed laws making it illegal for a person to give a gun to a minor without the parent's permission, or to buy a gun for someone who can't own it legally.
But the legislature did not pass a law requiring background checks at gun shows, prompting Mauser's group, SAFE Colorado, to put it on the ballot.