I haven't thought this all the way through yet, but maybe the mole is the vice president. It sounds like he's about to make a play for presidency, and he seems to have the most to gain from a terrorist attack under these circumstances. He just seems like a slimy character overall.
Not trying to be mean at all, but that makes zero sense. The amount of security around him, people watching, protecting him all the time, he'd never have the chance to do anything like that. And it doesn't sound like he's making a play for the presidency, it sounds like him getting to attempt to succeed a lame duck Pres.