Mayor Michael Bloomberg is stepping up his gun control campaign by asking donors not to support four Democratic U.S. senators who opposed a bill to expand background checks on gun buyers.
In a letter, Bloomberg names Sens. Mark Pryor of Arkansas, Heidi Heitkamp of North Dakota, Max Baucus of Montana and Mark Begich of Alaska, all of whom, he says, opposed the legislation that was defeated in April.
"I am writing to ask you: The next time these four senators want you to support them with donations to their campaigns, tell them you cannot," Bloomberg wrote to about 1,100 New York City residents who had contributed to the senators. "Until they show they will stand up for the American people and not the gun lobby, tell them you cannot support their candidacy."
Pryor and Begich are up for re-election next year. Heitkamp doesn't run until 2018, and Baucus announced April 23 that he is retiring and won't run again next year.
Pryor has said he didn't vote for the background check measure because he believed a separate gun control measure he supported, written by Republican Sen. Charles Grassley of Iowa, was stronger. He also said the bill would not have prevented the Newtown, Conn., massacre and other mass shootings.
The gunman in Newtown killed his mother and then 20 children and six adults at Sandy Hook Elementary School before committing suicide.
Heitkamp said she felt the bill would place undue burdens on law-abiding citizens. Begich said the measure would have undermined Second Amendment rights. Baucus said he was voting in accordance with what his constituents wanted.
The appeal to withhold contributions from Democratic candidates has raised concerns among party leaders that this could affect the balance of power in the Senate in the 2014 midterm election.
Democrats hold 52 seats, along with two independent senators who caucus with the majority party.
Turning over the Senate to Republican control, Democrats warn, could make passage of gun control legislation impossible, undermining Bloomberg's broader goal in the process.
Bloomberg, an Independent, in an interview yesterday on MSNBC's "Morning Joe" program, dismissed the notion that targeting Democrats could harm the cause of gun control. He said he is patterning his single-issue approach after that of the National Rifle Association, which grades candidates on their gun votes.
"The NRA has defined how you go about getting something done," he said on the show. "We're judging you, we're not judging your opponent. We'll deal with your opponent at a different time. We want you to vote this way. This is what's right for the country."