Well, CF could have been referring to the historical tendency of the party of the President to lose congressional seats in the administration's sixth year.
Yes, and that would be some odds. The GOP still has fundraising in its corner, a historical trend in voter registration and recent voting patterns, a limited number of vulnerable seats due to incumbency protection, and a better (less worse?) approval rating than the Dems -- and a proven fundraiser in President Bush that is more popular (less unpopular?) than both Congressional parties.