If there’s anything I could get people to understand about the next election, it’s this: Even a 2006 or 2010-esque tsunami might not give Democrats control of the House.
That might seem shocking. In 2006, Democrats won 31 seats; Republicans won 63 in 2010. Today, Democrats only need 17 seats—which might not sound like much.
But the fact is that Republicans just aren’t exposed. To turn the “tsunami” into an extended metaphor, an unprecedented share of the Republican caucus has evacuated to high ground.
There are only a handful of Republicans on Democratic-leaning turf—just two with a Cook PVI of D+2 or more, which measures how a district voted in recent presidential elections compared to the country. In 2006, there were 18 Republicans on similarly Democratic terrain, while a whopping 59 Democrats held lean-Republican districts heading into 2010.
This makes it hard to imagine huge Democratic gains. Tsunamis tend to flip the majority of incumbent party seats on hostile terrain, but the incumbent party still retains the majority of seats on even or slightly favorable turf.
If you plot this out, there’s a roughly linear relationship between PVI and the share of incumbent party losses. On the other hand, you can make the case that there’s something of a break around C+2, where perhaps the incumbent party becomes significantly less likely to retain its seats.
Regardless, if today’s Republicans lose at the same rates as the incumbent party in similarly partisan districts in 2006 and 2010, they’d only lose about 20 seats, depending on your assumptions about linearity. That would barely be enough to flip the House. Realistically, it would be a long election night, with the outcome decided by recruitment, retirements, fundraising, and turnout.
And there are reasons question whether Democrats could gain seats at the same rate as the challenging party in 2006 or 2010, even if the national climate is just as favorable. For one, there are fewer Republican retirements. In 2006, Democrats won 6 open seats in districts that were R+3 or more Democratic. Today, there’s only one open seat in such a competitive district (FL-13).
Just as importantly, many of the ‘06 Democratic victories on heavily Republican terrain were the result of corruption. By my count, 7 of the 12 Democratic pick-ups in R+4 or more Republican districts were assisted by Abramoff, federal investigation, or other scandal, including seats held by Delay, Ney, Foley, Pombo, Heyworth, Taylor, and Sherwood.
I can’t predict whether there will be a Democratic “wave” next November. History gives us cause to doubt it, but recent polls definitely make it conceivable. But if you’ve been assuming that a “wave” would result in a Democratic takeover, you might think again. It would be a long Election Night.