Recent polls show more than 90 percent of Americans support requiring background checks for firearms purchases at gun shows.
The "gun show loophole" allows criminals and the mentally unstable to buy guns when reputable dealers would refuse to sell to them, gun control advocates claim.
Support for the background checks crosses political lines, with more than 9 in 10 Republicans agreeing with the measures.
But change has been slow in Congress, particularly among conservative Republicans whose base is heavily courted by the National Rifle Association, the most powerful and influential lobbying organization for gun manufacturers.
So some states are moving ahead with gun control measures on their own. After a sting operation in which undercover agents were able to purchase weapons, including several military style assault rifles, without showing identification at six gun shows in New York, the state is now mandating criminal and mental health background checks at shows statewide.
The New York attorney general's office threatened gun sellers with criminal prosecutions, so most sellers across the state have instead agreed to voluntarily enact the new background checks.
"Our goal is to have 100 percent of the gun show operators on board, and then we have a good example for other states to follow," Eric Schneiderman, attorney general of New York, said.
"Once we demonstrate how easy this is, and how it keeps people safe, it weakens the arguments on the federal level that guaranteeing background checks are overly burdensome or face meaningful opposition."
If the program works, it's possible similar legislation could be introduced on a national level in Congress, but it's equally likely that New York's requirements could be struck down in federal court.
Gun rights advocates have doggedly opposed any restrictions on firearms purchases, and recently the courts have been more favorable to their cause than public opinion.