"He has said no, but I would certainly hope that he would serve, if asked, as vice president or attorney general," Trippi said. "There are a lot of us who hope he will get asked and that he will serve."
With McCain securing the Republican nomination Tuesday night, and Clinton and Obama entrenched in a fight that could go all the way to August's Democratic Party convention in Denver, Republicans hope that a drawn-out battle will be a disadvantage for Democrats going into the general election.
Trippi said even if the nomination is settled on the convention floor, the Democrats will mount a vigorous general election campaign.
"Look at the energy, the money, the massive turnout. These are two candidates that Democrats are very excited about," Trippi said.
"Either one of them on their worst days raised more money than McCain's been able to raise, and has more excitement and energy and have turned out more voters than McCain's turned out," he said. "I'd be really worried if I were on the Republican side right now."
ABC News' David Wright, Sunlen Miller, Jake Tapper and Avery Miller contributed reporting.