Or maybe Truman. But yeah, he's that kind of figure.
Nader's no whackjob. I would say that it's someone in some sort of "wait for the zombies to rot" party. Some member of the fringe left, probably.
Since the elections occur while the safe zone is still being established, I could also see a "Revenge for Yonkers!" candidate who wants to abandon the Redeker plan and go full conventional warfare on Zack. Also, a "This is God's Punishment for Our Sins!" candidate (probably a rightist televangelist-sort) and a "We Must Make Peace With the Dead" candidate who spreads the early nuttiness that the zombies can be reasoned with / worked into society.
John McCain is still a contender for the 2008 presidency, IMO. He was born in 1936, so would have been 72 when elected, the oldest president upon inauguration. Even for someone in excellent health, the stress of the events would have taken a massive toll. As for Carlson's "propped-up patsy" remark, part of it may have been Carlson's contempt for pretty much everyone, part of it the political machine feeding everyone the party line, and part of it just being in a completely unseen and frankly unimaginable situation, and relying on 'expert advisors' for a plan to follow.
Also, I'm pretty sure the election they talk about is 2012. So, Alt!Powell is President from 2012 to within one year of Victory in America day. It took three years for the U.S. military to reclaim all the lost territory after an unspecified number of years in the safe zones, according to Waino's narration. Also, it would be another two years from VA day until Victory in China day, considered the 'end' of WWZ.