If Democrats lose a net of eight House seats, will that be a lot or a little?
How will you know?
Of course, at a very important level, only one metric counts in measuring the outcome of the November elections: Do Democrats maintain control of one or both houses of Congress?
The history of the next two years, of the Biden presidency and perhaps of the world itself will be powerfully influenced by that result.
Yet, declaring that Democrats will have done a great job if they hold their current Senate margin, but a terrible job with a net loss of one seat (or lose four House seats vs. five) would seem like over-interpretation.
Normally we think of success by way of comparisons. Did my stock go up more or less than the market average?
Start with the simplest. In the 19 midterms since the end of World War II, the party holding the White House has lost an average of 27 House seats and four in the Senate.
Holding these bodies this year would require an outstanding showing by Democrats, that is, one far above average.
But averages can obscure as much as they reveal. House seat changes in those 19 midterms ranged from plus eight to minus 64, averaging minus 27, while the Senate ranged from plus three to minus 13.
Emory political scientist Alan Abramowitz provided another useful set of comparisons, bucketing these 19 midterms based on seat losses, in a newsletter run by his University of Virginia colleague, Larry Sabato.
On the Senate side, the presidential party actually gained seats in four of the 19 midterms, while in another four elections it lost between zero and one seats. Three cycles saw net losses of two to four, and in another three years, five to seven seats fell. In the five worst Senate midterms for the president’s party, it lost eight or more seats.
Democrats retaining control of either body will require an historically Herculean performance.
Of course, we can’t know how this election compares to the historical record until the votes are tallied, but the comparison will be instructive in assessing just how well Democrats did.
Another useful comparison is based on how well Democrats did, given the fundamentals. You’ve heard me drone on about fundamentals before — presidential approval, the economy, etc.
Elections take place in a context, and that context plays an important role in shaping the outcome. For example, it’s easier to win your race when your president is at 65 percent approval than when he (or someday she) is at 45 percent.
Professor Gary Jacobson of the University of California, San Diego modeled the fundamentals and calculated that Democrats are likely to lose about 45 House seats this cycle. That would put this midterm among the very worst for the party in power.
Anything better than that and Democrats will have “beaten” the fundamentals.
Whatever comparisons you employ, however, it’s worth recognizing that it is only by making appropriate comparisons that we can judge how well each party really did.
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 more than 20 years, as president of the American Association of Political Consultants, and is president of Democratic Majority for Israel.