Capitulating to criticism of elected officials mixing politics and charity, the Georgia-based insurance giant AFLAC Inc. pulled the plug Wednesday on a concert for big-money donors that had been scheduled for July at the Democratic National Convention in Boston.

The event had been pitched as a fundraiser for cancer charities, but after coming under fire Tuesday from a liberal ethics watchdog group, Sen. Blanche Lincoln (D-Ark.) abruptly withdrew as chairwoman of the benefit.

Lincoln’s decision, in turn, led AFLAC on Wednesday to announce its cancellation of the July 28 “Rockin’ the Dock of the Bay” event. The event would have honored seven Southern Democratic Senators and solicited donations ranging from $2,500 to $100,000.

AFLAC, which has long supported causes associated with childhood cancer, had guaranteed $100,000 for the event. The event was also sponsored by several other companies.

AFLAC is scheduled to sponsor a similar concert event at the Republican National Convention in New York. But the fate of that event — chaired by Sen. Saxby Chambliss (R-Ga.) — is unclear. AFLAC officials did not return several phone calls inquiring whether the decision to cancel the Democratic event would affect the GOP event. A spokeswoman for Chambliss said she was unaware of any change in plans.

AFLAC said it had hoped to raise $250,000 for the charities at each of the conventions. But critics — led by Citizens for Ethics and Responsibility in Washington, a nonprofit group led by a former federal prosecutor and Democratic Congressional aide — contended that the high-priced concerts were designed to sidestep new restrictions on soft money and to provide special interests with a way of seeking favor with powerful lawmakers.

CREW said the Senate Ethics Committee, of which Lincoln is a member, should issue an opinion that prohibits Senators from associating with charitable activities at the conventions.

Melanie Sloan, CREW’s executive director, said she welcomed the decision by AFLAC to cancel the event and said the burden is now on Republicans to explain why they are holding such an event. The group’s complaint to the Ethics Committee also cited a charity concert and reception hosted by Senate Majority Leader Bill Frist (R-Tenn.) that is scheduled for the convention and which would benefit several AIDS groups.