1. Tea Party
Recent polling shows that more and more Americans have an unfavorable viewpoint of "Tea Partiers." But the Tea Party has managed to defeat several GOP candidates in primary elections, giving the Dems a better chance come November. Here's an example: for months Harry Reid couldn't even poll above 30% in his quest for reelection, but is now leading. I think this effect will happen in half a dozen more races giving the Dems some wins on November 3rd.
The Democratic Party is always bad at messaging. I mean, we're liberals, what do you expect (have you ever read my blog?)? But now, more voters are paying attention and messaging becomes crucial. The Democrats need to show a stark contrast between themselves, a party that has kept this country from dipping into a Depression, and the Republican Party of "No."
According to many accounts, Democratic candidates and the Party itself have sizable financial advantages over their opponents (thank you Michael Steele!). And although this may not save every candidate from losing, it could help create a firewall.
Overall, I expect the Democrats to lose the House of Representatives, but hold on to the Senate. I put the chances of this scenario at 75% due to recent generic ballot polling. There are, however a myriad of variables which come in to play that make this election cycle different from 1994.
Edited by John O'Connor