Jimmy Carter has been among the country's most active retired presidents, but even the peripatetic Georgian might not have anticipated having his name bandied about in a presidential campaign 28 years after leaving the White House.

Sen. John McCain, who will carry the Republican presidential flag in this fall's campaign, has repeatedly invoked the former president's name on the campaign trail, and with it the less-than-stellar memories of his White House years. Some high-profile allies, including Texas Gov. Rick Perry and former GOP presidential contender Mitt Romney, have done so as well.

The goal: linking Barack Obama to Carter, another Democratic newcomer elected on the promise of hope and change but whose presidency was marred by economic turmoil, high energy costs and a foreign policy widely derided as weak.