NATIONAL SECURITY and TAXES: On these two issues that inspire emotion among loyal Republicans and many swing voters, Republicans have long had an advantage, and President Bush and other prominent figures in the party will be pushing those messages hard.
INCUMBENCY: It is mathematically impossible for Democrats to win control of the House or Senate without beating a large number of current Republican officeholders. Incumbency brings many advantages, and lots of the Democratic challengers are inexperienced politicians who may collapse after a debate gaffe or an attack ad.
These advantages have benefited President Bush and his chief strategist, Karl Rove, in the past. And Republicans are now playing with maximum focus to limit their losses, rather than to win.
So before Democrats go predicting three weeks out that a takeover of Congress is inevitable, they would be wise to remember another warning from Berra.
It is still possible that the party of Howard Dean and Nancy Pelosi will experience "deja vu all over again."
Mark Halperin, the political director of ABC News, is co-author of the book "The Way to Win: Taking the White House in 2008" with John F. Harris of The Washington Post. Go to thewaytowin2008.com to find out more.
