[Quilla]

Isn’t it a bit unseemly for a republican to run against the incumbent?

[C19fan]

Reagan ran against and almost beat Ford in 1976.

[Robert A Cook PE]

Isn’t it a bit unseemly for a republican to run against the incumbent?

But aren't you assuming Romney (or McCain, McConnell, Ryan, Graham, Thune, Chamblis, ....) are actually republicans? (Well, they certainly are NOT conservatives!)