The upset election of Scott Brown to the vacant Senate seat held by the late Teddy Kennedy seemed to be further confirmation of what we described in this post as the “Obama plunge.” This term referred to our belief that the percentage of the vote Barack Obama and/or Democratic Congressional candidates received in 2008 was a high water mark for Democrats, and that there has been a consistent decline of 12-15% in Democratic performance since that election – particularly after the “cap and trade” vote that was taken in the House last summer.

Given this recent decline in Democratic performance, we used the following criteria to determine how many House seats would flip to the GOP, which led us to believe the GOP would potentially pick up a net of 79 seats in the House (80 Democratic seats minus the Republican held seat in New Orleans):

(1)   An Obama vote of 65% or less;

(2)   For incumbent Democrats, a 2008 re-election percentage of 65% or less;

(3)   How incumbent Democrats have voted on major legislation (the stimulus, “cap and trade”, raising the national debt ceiling, and the five healthcare votes taken), with the idea being that voting against the Democratic agenda a majority of the time insulated an incumbent from defeat. We further modified this rule in this post to state that even one “Yes” vote (out of five possible House votes – there was another healthcare vote today in the House that passed 220-207, with 32 Democratic defections) on healthcare meant defeat.

So where do these vulnerable Democrats come from ? While 24 Democrats in this total come from New York, Pennsylvania, and Ohio alone, all in all, 33 states are represented in this total. There is also some geographical dispersion to these vulnerable Democratic seats are, as the Midwest has 22 seats, the Northeast 19, the South 17, 10 in the Rocky Mountain States, 6 in New England, and 5 in the Pacific Rim states. Of particular concern for the Democrats are the numerous vulnerable seats in the Midwest and Northeast, since these states have voted nearly unanimously Democratic since the 1992 Presidential election.

Election data and voting records can’t perfectly predict the ultimate outcome of the November elections, however, because of the following factors:

(1)   Candidate filing is still open in 30 states representing 227 (out of 435) House districts. While retirements have been kept to a minimum over the past few months (likely because the Democratic leadership needed their votes for the healthcare reform package that just passed), it is still possible for there to be more retirements before the last filing deadline (in Delaware) on July 30;

(2)   We are assuming that all open Democratic seats which gave Barack Obama 65% of the vote or less are GOP pickups, while the GOP will hold onto all its open seats. This assumption, even in a landslide, is not an 100% safe one, as even in landslide years, the losing party will still pick up some seats;

(3)   As we saw recently with former Congressman Eric Massa (D-New York), incumbents can suddenly become ensnared in scandal between now and the November balloting. In those situations, either the incumbent quits or they see their electoral fortunes crumble;

(4)   The personal popularity of incumbents or the presence of strong third party (sometimes even fourth party) candidates can alter the results as well, even in landslide years.

Having added these caveats, it is worth exploring a few more “what if” scenarios in analyzing the November outcome as of the time this article is being written:

(1)   Currently, we are assuming that a Democratic incumbent who received more than 65% of the vote in 2008 is insulated from defeat, regardless of how he/she voted. The healthcare vote, however, has shattered that assumption, as there are an additional 65 formerly “safe” Democrats (over and above the 80 we have already deemed as vulnerable) who voted “Yes” on healthcare reform at least once. Interestingly, this group of supposedly “safe” Democrats includes Michigan Democrat Bart Stupak (whose abortion compromise with President Obama enabled healthcare reform to pass) and Massachusetts’ outspoken liberal Barney Frank.

(2)   The “Obama plunge” we have observed has been in the range of 12-15%. We have based our calculation assuming that there is a uniform plunge of 15% in each district. However, the 15% figure only occurred in Massachusetts. What if the real “plunge” were 12% (which was what happened in New Jersey, Virginia, and the 10^th Congressional District in California) ? Our data shows that a projected 79 seat gain for the GOP would be reduced slightly to a net 70 seat gain for the GOP;

(3)   Just as a “Yes” vote will not guarantee defeat for an incumbent Democrat, a “No” vote doesn’t guarantee re-election, either. There are 10 Democrats who have, in addition to voting “No” on a majority of the Democratic agenda, voted no on all five healthcare votes, but could still be vulnerable to the right Republican opponent or a general “throw out the bums” mindset, particularly if they had supported “cap and trade” or the stimulus.

In conclusion, this analysis is one we will continually revisit as (1) filing deadlines come and go, (2) more controversial votes are taken, and (3) once party nominees have been selected, we will start analyzing poll data to refine the list of vulnerable Democratic or Republican held seats.