The name-calling of Sen. Marco Rubio by a gun control group started by media mogul and New York Mayor Michael Bloomberg intensified on Thursday after the Florida Republican helped defeat a congressional measure expanding background checks for nearly all firearm buyers.
The leader of the Mayors Against Illegal Guns group in Rubio's home county of Miami-Dade, Democratic Pinecrest Mayor Cindy Lerner, said at a press conference that Rubio's vote the day before was all about his ambitions for the White House in 2016.
And, Lerner said, Rubio's position on guns will cost him dearly when he runs again for office.
"Your position and your vote yesterday put you on shaky ground with 94 percent of Floridians," Lerner said, citing a poll paid for by the group that showed overwhelming support for "universal" background checks.
"You are a coward, Sen. Rubio," she said. "You are afraid to stand up to the gun lobby and to stand up for your constituents. Instead, you stood up for the NRA. Shame on you."
Rubio's office declined comment.
Rubio said recently that he opposed expanded background checks because they don't work.
Those who buy firearms from licensed dealers must undergo a background check, but there's an exemption for private sales. Some of those private sales can occur at gun shows, which is why the exemption is known as the "gun show loophole."
Rubio said if gun control advocates are concerned about mentally ill people and criminals getting guns, they should work toward improving the mental health system and society at large.
"We are missing a golden opportunity to have an open, honest, and serious conversation about why it is that we are having these horrific violent acts occurring in our society," Rubio said Sunday on CNN.
The mayors group earlier this month made a modest advertising buy in the Tampa and Orlando media markets criticizing Rubio for his position on guns, saying it makes people less safe.
The group wouldn't disclose whether it plans to spend significant sums of money to defeat Rubio. He's up for re-election in 2016, but could go after the White House as well.