I think they're making a huge mistake. Look, they're going to lose on the defense issue, but put that aside. The reason, IMO, Clinton was never removed from office was that people didn't want him removed. They didn't WANT Algore in the hot seat. They didn't WANT the national turmoil we went through with the Nixon resignation. They didn't WANT to rock the boat and screw up the boom times.
I didn't like Clinton, but I didn't want him impeached. I wanted him to quietly serve out his last two years in office. People feel the same way now. Whatever real or imagined crimes W may have committed, we can't afford to have the goovernment tied up in knots right now.
Impeachments are a peacetime pastime, historically. The rats are going to find to their chagrin, that the American People can be very single minded in war. That saying "People vote their pocketbooks" has an essential corollary -- "except in times of war."
The ultimate argument of the left seems to be over whether we're really at war or not. I sure hope we answer the question correctly in November. I think we will.
It takes a long time to turn the Ship of State. I think we forget this, and at our peril.