In the last post you concluded that a President’s party loses seats because they win those when the President is elected and then revert back to “normal" the following election? Is it the same in the Senate?
No. The Senate is different than the House. In the House, all 435 seats are up every two years. Thus, a Republican leaning district that goes Democrat is likely to go back to the Republicans in the next non-Democratic election.
The Senate only has a third of the seats up every two years. In a Republican year, like this one, Republicans can count on gains in Republican House districts because all Republican districts are up this year. The Senate has another factor, which seats are actually up for election. Democratic losses could be limited because roughly half the senate seats up for election are Republican seats.
In Democratic years like 2006 and 2008, the Democrats made gains in both houses. Two thousand four was a Republican year that showed good gains in the Senate but only three in the House. Republicans were near their peak in the House, but the Senate field was 21 Democratic seats and 15 Republican seats. Thus, Republicans had more opportunity there.
In 1986, Republicans lost five House seats and eight Senate seats. They weren't bloated in the House, but they won 12 Senate seats in 1980. They needed a very Republican year to hold onto those seats. A more neutral year resulted in a lot of losses. Sometimes a wave leads to gains in the Senate as well as the House, but only if there is opportunity.
So it's a Republican year in terms of electorate. Is it a Republican year in terms of opportunity?
No, but that might not be a bad thing. Republicans have 18 seats up this year, but only 23 in the next two cycles. Democrats, on the other hand, have 19 up this year and 42 in the next two cycles. You'd like to have your most vulnerable seats up when you're least likely to lose them. The Republicans would win more seats if more Democratic senators were up this year, but they'll likely gain the most seats by having so many Democratic seats up when the field isn't tilted toward them.
So what does this year look like?
The vulnerability number is determined based on PVI, with vulnerabilities of 6-10 proportional to the other party's PVI, while 1-5 were proportional to the party's own PVI.Despite a fairly equal number of seats up, the Democrats have the four most vulnerable seats up this year. On the other hand, each party has four seats up in swing states. The opportunity for Republicans should result in them winning 3-5 seats. Anything more than five will be a great Republican year.
Does that mean the Senate won't flip?
Probably. Republicans need the landscape so slanted that they don't lose swing states, pick up opportunity and swing states along with two seats that are in big Democratic states. That's why a small shift in polls could result in California, Nevada, and Washington could result in Democratic retention.
How does the future look for the two parties?
Tough on Democrats. This year Democrats have 8 vulnerable seats to the Republicans 4. In 2012, they'll have 12 to the Republicans' 3. Democrats took almost all the seats they could in 2006. They'll need a landslide at the polls just to retain them.
Where the Republicans shouldn't do better than win 3-5 seats this year, if that, they should net at least 6 and maybe as many as 10 or 11 in 2012. Thus, we could see the Senate flip to the GOP in 2012, while seeing the House flip back to the Democrats.
It's even worse for the Democrats. Almost every seat in play will be Democratic seats. While 2012 losses could be mitigated by another Obama landslide, Democrats won't have a Presidential race in 2014. The Republicans could easily win 6 seats this year, 7 in 2012, and another 8 in 2014.That'd give them 62 senate seats, a filibuster proof majority. Of course 2016 could be a tough Senate year for the Republicans, based on gains this year, but that's a long time in the future.