The former Obama aides who co-host Pod Save America have stood out as voices of political maturity. They predicted that Democrats’ chances of taking over the House are no better than 50-50 and even worried that Democrats could “lose everything.” But really, this should be no surprise and suggests that Democrats should temper their expectations, if not their hopes. Even if they win the House, it would be a normal course correction, not a repudiation. On average, the party in power has lost 24 House seats in the midterm elections in the postwar era, just one more than Democrats need to make Nancy Pelosi Speaker again. And the presidents who did not lose House seats in their first midterm election were Lyndon Johnson and George Bush in 2002, the year after 9/11.

With millions of ballots already cast — in more than a dozen states, it’s already more than the total number of ballots in the 2014 midterm — control of the United States Senate is probably already out of reach for the Democrats. More likely is that Republicans will expand their majority by 2-4 seats. A number of critical races will likely be very tight and things could change. In my home state of Arizona, voters have slowly discovered that Kyrsten Sinema is not really the centrist she has pretended to be and are turning toward the Republican candidate, Martha McSally, a former fighter pilot. Ms. Sinema is still the same person who said in 2006 that stay-at-home mothers are “leeching off their husbands” and that conservatives are “Neanderthals.” Yet, it’s still close and Ms. Sinema could still win. The enormous size of this year’s electorate makes polling even more difficult than usual.

In Texas, Beto O’Rourke, has raised far more money than Senator Ted Cruz and has captured the imagination of the political press, but has not led in a single poll and is currently far behind. Across the country, Democrats have consistently out-raised Republicans, but one of the lessons of this cycle may be that you can’t buy a wave election.

With Mr. Trump more popular than Mr. Obama just before the 2010 midterms, Republicans just might retain a House majority too, but if they do it, it will be close. Even if they don’t and Democratic gains there are balanced by Republican gains in the Senate, it is simply not a blue wave and is just a typical midterm adjustment by voters. What this would suggest is that Mr. Trump, or at least his policies, are much more popular than his media detractors believe.

This cycle was always going to be more difficult for Democrats than they thought. Even though the progressive agenda is embraced with almost religious totality by electoral supermajorities on the coasts and in many cities it is deplored almost everywhere else. That conflict is the basis for the sharp division in our politics. Democrats made a strategic error with the failed character assassination of Brett Kavanaugh. The viciousness of the choreographed, late-in-the-process attacks and Democrats’ rush to jettison the presumption of innocence disgusted many people who might otherwise have been more open to the Democrats’ message. And it did what Republicans had been unable to do for themselves: galvanize their base.