Michele Bachmann has not failed in her bid to be President of the United States due to some horrific sexist agenda. Sarah Palin did not fail in her not-quite-bid to be President of the United States due to some horrific sexist agenda.
They failed because they were lousy candidates.
In all seriousness, Obama has turned out to be a huge let down as president. He's there for the beating, and if the Republicans put forward a decent candidate, they would win. But if Palin and Bachmann are representative of the quality of Republican candidates, Obama might as well not bother campaigning; his opponents will do the job for him.
(Incidentally, that's not to say that there aren't horrific sexist agendas at work. But Bachmann and Palin aren't good evidence of them, since there are so many non-sexist reasons for rejecting them as candidates.)