That Democratic Majority

The Cook Political Report dissects all of the talk of a Republican re-take-over in 2010:
Of the 50 currently competitive seats, Democrats occupy 40 (80 percent), exactly the number of seats Republicans need to gain to steal the House majority. Of the 60 potentially competitive seats, Democrats occupy 45 (75 percent), a figure that underscores Democrats' overexposed position in the House today.

It is important to note that while one party has never won all of the competitive races in any given election cycle (currently Republicans would need to win all 50 competitive seats to win 218 seats in the House), the likelihood of one or two dozen potentially competitive Democratic seats entering the danger zone at some point in this cycle is high. We don't see the Democratic majority in immediate danger, but our current outlook projects a Republican net gain of 20 to 30 seats.
This is essentially what I've been saying as well. Democrats have a majority in both houses of Congress. Therefore the Dems really have nowhere to go but down. That said, Republicans would have to essentially have a clean-sweep of every competitive seat that is up for re-election. To me, that is akin to play the Hard Way in craps -- you never win.