Saturday, September 25, 2010

House Mid-Terms Explained

I’m sure I have some new readers who weren’t at the old site. So I thought I’d provide some House answers.

The President’s party always loses House seats in a mid-term. So they will this year. Right?
Wrong. What you’re doing is substituting an effect (the President’s party losing seats) for a cause (why they’ll lose seats).

Right. Right. Ok, The President’s party loses seats if his approval rating is below 50 or the economy stinks.
That’s sometimes a factor, but it’s not the most common factor.

Ok. Why are the Democrats losing seats this year?
There is currently a median center point of how the parties will divide up the seats. In an average year with no big factors, the breakdown will be no more than 10-12 seats from this number. There is a variance based on retirements, redistricting and other factors. The Democrats are likely way above this median point.

What is this median point?
Between 1944 and 1992 this was 246 Democrats and 189 Republicans. It was within 12 either way for half of the 24 elections. Only once did 3 elections pass without the parties being within 10-12 of these numbers. That was post-Watergate. The seats were within this range after 3 of the next 4 elections.

In 1994 there was a major shift. Many districts that were traditionally Democratic or swing districts became Republican districts. There were a number of reasons for this, but it was mostly due to the southern districts that had voted Republican for President since 1964 finally translated that to the House. Between 1994 and 2004 the split was always within 7 seats of Republicans 228 Democrats 207.

We don’t know the current median. It could still be 228-207, which would mean the Republicans would gain 49 seats net. It’s possible that a new period has started and we don’t know it yet. Based on current polling that median isn’t likely 256-179, the current split. Whatever the current split is, the Republicans are unlikely to overshoot it, since only once have there been three consecutive elections that weren’t close the median. There’s no indication that a new period has started. Since the House went to 435 members, the periods have changed with the Great Depression, the end of World War II, and the 1994 re-alignment.

Does that mean the Republicans are going to take the House?
Yes. In 2008 Barack Obama won 242 congressional districts and John McCain won 193. There were, however, 229 districts where McCain outperformed his average. So it’s likely that the House should average out to being a Republican majority.

Wait a second. Why would you count districts Obama won for McCain?
While 53%-46% is how Barack Obama did, the average congressman isn’t Barack Obama. Scott Brown won 57% of the vote or more in 5 congressional districts. We know that Republicans aren’t going to win 5 districts this year, but all 5 of those candidates should have a better chance than the 2 districts Brown won by small margins.

If we just took the 193 districts that McCain won, however, we find that 46 of them have a Democratic congressman. Of those, 21 flipped to the Democrats in either 2006 or 2008 and another 6 are open seats. In an average year without Obama the Democrats would likely lose many of them. In a Republican year, they’ll lose more.

But that doesn’t mean they’ll get 39 seats. That’s a lot.
True. But with Democrats recently taking McCain districts and the retirements Republicans would’ve taken at least 27-30 seats without the wind at their backs. In this environment the other 9-12 should come.

Republicans lead by an average of 7.2 points on the generic ballot among likely voters. In 2004, Republicans were 3 points better nationally and finished with 232 seats. All indications are that this will be a better year than 2004 for the Republicans.

You never answered the first question about the President losing seats in a mid-term.
The two charts below are how a party did when a new President was elected or was re-elected.

As you can see the President’s party usually either stays within 6 of the average, if the President doesn’t have coat tails, or overachieves by 20 or more seats, if he does. Jimmy Carter actually did exceptionally well. While his party gained only 1 seat, they had a bloated number due to their 1974 Watergate wins. They were still above the number until Ronald Reagan won.

That’s a Presidential election. What about mid-terms?
Since a party often ends up way above the median when they win the Presidency, the mid-terms are a come down.

As you can see most Presidents were way above their median, and were expected to lose seats. Here we can see Eisenhower (1st mid-term) and Carter’s losses actually out performed the average. It’s no coincidence that the worst performer was the Republicans during Watergate. We can also see that one of the big reasons why Clinton didn’t lose seats in 1998 and Bush didn’t in 2002 was that they weren’t burdened with a lot of the other party’s seats to defend.

Republicans did win 54 seats in 1994, but, if we’d known the median, we would’ve expected them to win 51. What we do see here is that based on the usual mid-term performance the Republicans are unlikely to overshoot the median, and, if they do, it won’t be by much. That’s good news for Democrats if the median has them with the majority.

From the re-election chart we can see that if Obama wins re-election, he’s pretty much certain to get the Democrats back to the median if they fall below that.

On the other hand, 2 of the 3 sitting Presidents who lost their Presidency suffered House losses much higher than expected.

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