Flake's office responded Friday morning with an email to TPM. Spokeswoman Genevieve Rozansky disputed the ad, and pointed to Flake's vote in favor of a piece of legislation that was supported by the nation's largest gun lobby, the National Rifle Association, and sponsored by Sen. Chuck Grassley (R-IA).
"Contrary to the ad, Senator Flake did vote to strengthen background checks," Rozansky said in the email. "Senator Flake believes that the Grassley Amendment is a proposal that can pass both the Senate and the House and will greatly improve and strengthen our background check system."
The tactic has been repeated by conservative senators who voted against a popular measure hatched by Sens. Joe Manchin (D-WV) and Pat Toomey (R-PA). Their proposal would have expanded background checks for purchases made at gun shows or online. The Grassley legislation, meanwhile, would have done nothing to expand the instances where background checks would apply. Instead, it would have set aside money to add mental health data to the national background check system, and it would have restored gun rights for those who have been in a psychiatric hospital for observation or committed themselves voluntarily and were subsequently deemed recovered.
The latest ad from Mayors Against Illegal Guns was designed to seize on those sliding poll numbers by portraying Flake as having deceived a grieving mother.
In the ad, Caren Teves, an Arizonan who, according to Mayors Against Illegal Guns, voted for Flake in 2012, held a letter she received from Flake earlier this year. She got the response after writing to ask him to support legislation to expand background checks.
"My son Alex was killed in Aurora, Colo.," Teves said in the ad. "We wrote Sen. Flake, urging him to support background checks. Sen. Flake wrote, 'I am truly sorry for your deep loss, strengthening background checks is something we agree on.' One month later, Sen. Flake voted against strengthening background checks. The issue isn't just background checks, it's keeping your promise."
The commercial will begin airing Friday in the Phoenix and Tucson media markets and it will run through May 30. Mayors Against Illegal Guns also ran another ad last month in Arizona, attacking Flake for his position on background checks.
Watch the commercial, which is entitled "My Son," below.