You sound like someone who's never actually gotten involved in politics.

Try getting in at the local level--volunteer for a state representative's campaign, or a local city/county commissioner. Get to know people, talk to them, see what it's really like.

What you're characterizing as "eminently corruptible" and full of "abuse and overreach" actually makes a lot more sense when you step out from behind the keyboard (and its steady supply of anti-government, libertarian websites) and get involved.