At least Sorenson is smart enought to realize the following:

He's usually not
as dumb as he pretends to be.

Acting dumb is Bush's style. He likes to sandbag people. He plays
dumb, people underestimate him and, all of a sudden -- wap! He nails
them.

Harry still hasn't figured it out...which is precisely the reason why every
one of Harry's predictions about Bush have been wrong.