As a general rule, most criminal/corrupt officials aren't the brightest bulbs in chandelier. Getting ahead honestly with integrity takes brains that many politicians don't have. What they do have is a gift of gab, charm and persuasion; traits that are common to people with some degree of sociopathic tendencies.
I agree with you on this basic point, but the GOP has repeatedly blown opportunities at critical moments. They're throwing the fight. It's deliberate, and to describe their actions as "stupid" just camouflages what is actually happening, so I wish people would stop giving them that fig leaf.