New York Mayor Michael Bloomberg, in his latest bid for tougher gun control, is urging the city's legions of Democratic donors to withhold funds from four Democratic senators who opposed a background checks bill earlier this year.
The letter, sent to hundreds of the city's major donors on Wednesday, targets the four Democrats who joined Republicans in blocking a compromise bill designed to keep guns out of the hands of criminals, according to Mayors Against Illegal Guns, a group Bloomberg founded and largely funds.
The bill reached the Senate floor just months after a gunman killed 20 first graders and six adults at an elementary school in Newtown, Connecticut, prompting gun control advocates to push for significant changes to U.S. gun laws.
Most senators - 54 - approved the measure, which polls indicated was backed by more than 80 percent of Americans, when it came up for a vote in April.
The plan to expand background checks to sales made online and at gun shows failed to become law after Republicans threatened to use a filibuster to block any gun proposal that did not get 60 votes in the 100-member Senate.
It was a stinging defeat for the billionaire mayor, who had aggressively used his personal wealth and political bully pulpit to push the measure. At the time, Bloomberg called the defeat a "damning indictment of the stranglehold that special interests have on Washington." He said his group would work to defeat opponents of gun control in the 2014 midterm elections. Wednesday's letter, first reported by the New York Times, targets Max Baucus of Montana, Mark Begich of Alaska, Heidi Heitkamp of North Dakota and Mark Pryor of Arkansas.
"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. Until they show that they will stand up for the American people and not the gun lobby, tell them you cannot support their candidacy," the letter says. "These "no" votes were a slap in the face to Americans everywhere."
In scathing language, the letter criticizes the senators for undermining efforts to keep Americans safe, at the same time as they approached New York donors for contributions.
At least one of the senators targeted by Bloomberg said he relishes the challenge.
"In Alaska, having a New York mayor tell us what to do? The guy who wants to ban Big Gulps?" Begich told the New York Times. "If anything, it might help me."
The four senators were not immediately available for further comment.
Senator Joe Manchin of West Virginia, a Democrat and a chief sponsor of the bipartisan background check plan the Senate blocked, told reporters he would like to see more money going to "gun culture states" to finance an information campaign about why Americans should not fear the background-check expansion.
"It's well-intended, they all have different approaches and they have a right to have that approach," he said of Bloomberg's letter.
Others said the effort could backfire, especially if Republicans win back control of the U.S. Senate, making new gun control legislation all but impossible.
"Mark Pryor is the only Democrat who could win in Arkansas," said one senior Democratic aide. "Making it less likely that he will win, will make it more likely that Republicans take control of the Senate, which would doom the prospects for expanded background checks for the foreseeable future."
The aide said that in some states, Democrats targeted by Bloomberg could use the liberal New York mayor as a foil to campaign against. Still, the aide quickly added: "It is never good to have someone spend millions of dollars against you."
(Additional reporting by Thomas Ferraro)