An effort to recall two, Colorado state senators following their votes to enact two gun-control acts, could bring a chilling effect to lawmakers who have to cast votes of conscience instead the face of negative politics. The Colorado legislators passed a package of gun-control reforms, including requiring background checks on private gun sales and limiting ammunition magazines to 15 rounds. Gun-rights advocates warned that they'd go after any legislator they felt was vulnerable who supported the bill. Now, six months later, two Democratic senators are targets of a recall.

In the absence of federal action on gun control, the Colorado legislation drew national attention. Gun-control measures were being enacted in a Western state in which gun ownership is common but was also the site of two of the worst mass shootings in recent years, at the Aurora movie theater in 2012 and Columbine High School in 1999.

The battle has broadened beyond the effort to recall the state senators with money coming in from out of Colorado in support of the lawmakers. Donations supporting the recall effort have also flooded the district. National figures and groups - including New York Mayor Michael Bloomberg, The National Rifle Associaton and the conservative Koch brothers - have gotten involved and donated money.

The vote next Tuesday is shaping up as a proxy for the national gun control debate.

Supporters of the two embattled state senators, John Morse, the president of the Colorado Senate, and Angela Giron, also agree about the election's importance, but for different reasons.

If the recalls succeed, they say, that could set a dangerous precedent in which recall powers are abused to try to remove any elected official who casts a controversial vote.