AP Photo/J. Scott Applewhite

Sen. Patrick Leahy, D-Vt., pointed some of the blame for the failed Senate debate over comprehensive background checks at New York City Mayor Michael Bloomberg, who dedicated millions of dollars to eviscerating senators who opposed such legislation.

"Unfortunately, you have some on the left like the mayor of New York City, who actually didn't help a bit with his ads. He actually turned off some people that we might have gotten for supporters," Leahy, chairman of the Senate Judiciary Committee, said in an interview to air on C-SPAN Newsmakers on Sunday. "Then you have some on the far right who say that the second amendment allows us to have anything. I mean, you can take a machine gun to deer hunting. There needs to be a balance between the two."

In the weeks following the Senate's unsuccessful vote on the background check bill, Bloomberg poured millions of his own money into television ads attacking Republican senators like Kelly Ayotte of New Hampshire and Jeff Flake of Arizona, who voted against the legislation. Bloomberg also launched an airwave assault on Sen. Mark Pryor, D-Ark., a vulnerable incumbent in the 2014 election.

Bloomberg's tactics drew some earlier criticism from Democratic lawmakers on Capitol Hill advocating for stricter gun control who thought his ads were detrimental to the cause and also threatened Democrats' hold on the majority in the Senate.

"I spoke to the mayor this week - he and I have been friends for some time - to remind him just as I've reminded everyone here that to have Republicans in control of the Senate is a sure sign we will never ever get anything done," Senate Majority Leader Harry Reid said in June.

"Frankly, I don't think Bloomberg's ads are effective," Sen. Chuck Schumer, D-N.Y., said in June. "The mayor of New York City putting ads against people in red states is not going to be effective."

Americans for Responsible Solutions, the group founded by former Rep. Gabrielle Giffords and husband Mark Kelly, also ran ads criticizing senators who voted against the legislation.

Leahy predicted the background check bill will not make it back to the Senate floor.

"It is not going to get through now," Leahy said. "It's unfortunate because, Could you pass one law that would stop all the gun violence in this country? No, but can you do a lot better than we have? Yes."