You're not paying attention to how Congress works. For two instances, Impeachment bills and spending bills start in the House.
The moonbat Left would love to spend 2 years on Impeaching Bush. And they could cut off all spending for Iraq, forcing us to leave in disgrace. That's how we left Viet Nam.
Vetos wouldn't stop either action.
I'm very aware of both but it could cause political hell to pay for the Democrats if they tried either one, particularly now that the whole Plamegate thing has been exposed as an enormous lie.