They don't wield authority save at the Army's behest, and the Army seems fine with the corruption; indeed, it probably worries more about politicians who aren't. People who are too perfect have suspect loyalties in a crooked enterprise like the State of Pakistan. For rather than the straight divisions offered by the American Constitution, in practice in Pakistan the only check-and-balance seems to be that no high ranking official - civilian, judicial, or military - is fully legitimate or has "clean hands". (Consider how the last few PMs have reached office.)
That some Pakistanis study at Oxford and Cambridge doesn't always have to do with corruption.
You're too generous. Some American politicians are crooks and do end up in jail - though I don't recall stories of any being lynched in them.
Do you get your congressman's circulars? Does he or she not respond when you call their office for help or with a complaint? Don't they show ability to compromise some issues while pressing others? The failure of Pakistani politicians to fulfill (or even attempt!) these basic tasks is what led to the collapse of government in the fifties, seventies, and nineties.
