A blue wave is building, but it will crash into a relatively stable political system surrounded by high walls. The damage that wave will do to the GOP depends on the height of the wave relative to the walls — and no one can confidently assess that yet.
While Democrats understandably cheer every poll highlighting the wave, few people seem to be contemplating the height of the wall.
Anyone who thinks 2018 is a slam-dunk for Democrats at this point either doesn’t understand our politics or is fooling themselves.
Trump’s historically low approval rating helps fuel the wave. When Democrats lost 63 seats in 2010, President Obama’s approval rating was 45 percent. Today Trump stands at an even lower 40 percent.
In recent weeks doubts have been raised. Headlines screamed about a tightening generic ballot — the question that asks which party respondents would vote for in a congressional election.
Polls showing a 16-point Democratic lead were way too optimistic and those showing a 2-point Republican margin were also far off. Drawing a line between the biggest Democratic margin and the smallest is silly. Down that road lies madness.
Besides the statistical anomalies, there is a clear pattern to these generic vote numbers over time and this year’s readings are following the pattern.
In January and February, they move toward the in-party, and from now through election day move toward the out-party.
Based on this history, analyst G. Elliot Morris predicts Democrats will win the national House vote by 10 points in November.
Make no mistake — that would be a big wave. To find a midterm margin that big for either party, you have to go back to the mid-1980s.
In 2010, Republicans won the national House vote by just under 7 points and picked up 63 seats.
Examining the differences between 2010 and today also helps illuminate the role of the wall.
Thirty-six of the seats Democrats lost that year were politically unstable — the House seats were held by Democrats, but the districts had voted for both George Bush and John McCain in the two preceding presidential elections.
That is, 57 percent of the seats the GOP took from Democrats had been voting Republican in the two preceding presidential elections.
This year, Republicans only hold eight seats that voted Democratic the two previous presidential elections.
A total of 55 of the 63 (87 percent) of the Democratic losses came in districts the GOP won in at least one of those two preceding presidential elections. Nearly all the action was in those seats.
This year only 28 seats meet that criteria — far fewer.
Some people argue that this sorting is simply the result of gerrymandering — and that is certainly part of the problem.
But it is not the whole problem. County lines are fixed and aren’t gerrymandered from census to census.
In 1992, Bill Clinton won 1,494 counties. In 2016, Trump was victorious in 2,680 counties, while Hillary Clinton won just 454. Of course, she won the popular vote while losing the Electoral College. Barack Obama won both, but prevailed in just 833 of our over 3,000 counties.
Voters have been increasingly sorted and Democrats have become increasingly concentrated, not just by nefarious gerrymandering, but also because we live in urban areas and urban areas have become more Democratic.
Whatever the cause, the end result — districts tending to consistently support one party or the other — adds to the stability of the system.
At the same time, instability is introduced by the record number of open seats this cycle: 53, 36 of which are now held by Republicans.
2010 featured only 39 open seats in total, just 17 of which were Democratic.
The opportunity in open seats this cycle is vastly greater than it was for Republicans in 2010.
At this stage we are probably able to see the size of the wave more clearly than the height of the wall, but it’s their relative size that will prove dispositive.
Mellman is president of The Mellman Group and has helped elect 30 U.S. senators, 12 governors and dozens of House members. Mellman served as pollster to Senate Democratic leaders for over 20 years and as president of the American Association of Political Consultants.