Inside Mr. Obama’s Chicago headquarters, senior advisers had already worked to calm younger staff members by counseling them to tune out the natural, if jarring, gyrations of a closely fought presidential race. Supportive Democratic governors were doing the same on Tuesday. “Did we forget no-drama Obama?” Gov. Brian Schweitzer of Montana asked in an interview, reprising the go-steady slogan of Mr. Obama’s 2008 effort…

“I wouldn’t use the word ‘panic,’ but there is a sense that everything the campaign told us about the need to continue the fight is absolutely true,” said Justin Buell, a member of Mr. Obama’s national finance council in San Francisco…

Some Democrats questioned just how much Mr. Obama would gain from his Big Bird commercial. “I don’t think anyone would argue this ad will make any sort of contribution to the decision in this race,” said David Doak, a longtime Democratic advertising strategist, who added that it could be more effective in getting free attention from the news media, which it did.