Mark Pryor
Pryor is a Democratic senator from Arkansas.

Sen. Mark Pryor, D-Ark., still under pressure for not supporting a gun control bill in April, is fighting back against his critics. In a new ad released Thursday, Pryor took aim at New York City Mayor Michael Bloomberg and those in Washington, D.C., who have taken issue with his vote against gun legislation that would have expanded background checks to gun shows and Internet sales.

Facing re-election in 2014, Pryor is considered among the most vulnerable Democrats in an election that is more than 500 days away. He is taking heat from both Democrats and Republicans.

Just two weeks ago, Bloomberg’s coalition Mayors Against Illegal Guns purchased a reported $350,000 worth of ads criticizing the senator in his own state. The coalition’s ad used the death of Pryor’s friend Bill Gwatney to urge the senator to change his vote. Gwatney was chairman of the Arkansas Democratic Party. He was shot and killed in 2008.

Republicans seized the opportunity to pile on more attacks on Pryor last week, when the Senate Conservatives Fund released an ad stating that Pryor “votes like a liberal” and has changed since getting to Washington. The Senate Conservatives Fund is a political action committee founded by former Sen. Jim DeMint, R-S.C.

Pushing back against D.C. and Bloomberg, Pryor said the mayor is running ads against him because of his opposition to president Obama’s gun control legislation. Pryor defended his opposition to the legislation by saying that it would not have prevented any of the nation’s most recent gun massacres like the Sandy Hook shooting in Newtown, Conn., or the theater shooting in Aurora, Colo., if it had been law at the time.

“I’m committed to finding real solutions to gun violence while protecting our Second Amendments rights,” Pryor said in the ad below. “I approve this message because no one from New York or Washington tells me what to do. I listen to Arkansas.”

But who Pryor is listening to is still up for debate. A recent poll by Public Policy Polling found that a number of voters in red states are in favor of background checks. In Arkansas, researchers found that Pryor’s likelihood of re-election would increase if he had backed the background checks bill. Some 40 percent of voters indicated that they would be more likely to support Pryor next year should he reconsider his position. Only 34 percent of voters were less likely to follow suit.

Support for any form of gun control legislation in such a vulnerable Senate seat could be political suicide for Pryor. The National Rifle Association, which is America's largest gun lobby, would be on stand-by, ready to spend millions to defeat him. Gun rights advocates tend to rally and spend far more for the cause than gun control advocates do. However, this time around it seems Second Amendment advocates are finding major competition from the likes of the billionaire mayor.