not a perfect metaphor

I'd say start small - say, Vimes for President, then, once Sam has managed to make the entire field of candidates commit suicide, confess to past misdemeanours or simply go mad, then Vetinari can step in and restore order. That way all this messy constitutional business would be avoided and we can truly appreciate how excellent he'd be.

It also gives us scope for cunning subterfuge involving poisonous candles and the like...