“It’s sort of breathtaking that Paul Ryan made a whole speech about being truthful and making hard choices and yet he never mentioned a single idea of theirs — like turning Medicare into a voucher program, or a new $5 trillion tax cut they can’t pay for,” David Axelrod, President Obama’s chief strategist, said in an interview on Thursday, hours before Mr. Romney’s own acceptance speech. “They’ve spent an entire week not talking about their ideas because they know their ideas are unpopular.”…

“The audacity of mendacity,” Mr. Axelrod called it, in a play on the title of Mr. Obama’s 2006 book, “The Audacity of Hope.” He added, “It’s lying as a campaign strategy.”…

Mr. Obama this week, for the first time, entered the fray. Campaigning on Tuesday on college campuses in Iowa and Colorado, he told thousands of supporters not to believe the opposition’s attacks because, “how do I put this nicely? They will just fib.” On Wednesday in Charlottesville, Va., he ramped up his complaint, winning applause from the estimated 6,500 people.

“Sometimes they just make things up. But they’ve got a bunch of folks who can write $10 million checks, and they’ll just keep on running them,” he said.