Here are a few things to keep in mind about the next week's midterm elections.
Let me start with a preface. The Democrats could do fairly badly on Tuesday yet still better than presidential parties have historically performed in similar situations. This could be true without the election providing a clear message about which party or ideological faction is following the best political strategy. Pundits and politicians like election results to send a clear message about which political factions are right and wrong. People want elections to provide lessons. I'm not sure this one will. We'll see. There are many potential results "in the middle," where Democrats lose seats but not as many as parties in their position usually do, which won't provide an unambiguous lesson.
But regardless, the bottom line is that the president’s party always loses House seats when presidential approval is in the 40s. Since modern polling was invented, presidents have only gained seats in midterms when their approval was in the 60s. However, there are two unusual things happening in 2022 that lead me to think it is at least possible that 2022 will fit the historical pattern poorly. Or it might fit the pattern perfectly! Who knows! Either way, these two things greatly increase uncertainty.
First, no one knows exactly how much the Republicans' new lower education, lower social trust voting base will turn out without Trump on the ballot or in the White House. Will relying on these voters make it harder for Republicans to get the typical midterm out-party bump? Can only Trump, or the excitement of a presidential campaign, get them to the polls in high numbers? Usually, part of the out-party advantage is that they are relatively more energized than the in-party. Will this advantage be smaller because Republicans now rely more on Trump voters?
Second, another typical reason that the out-party has an advantage in midterms is that the president’s party has moved policy in its direction in the past 2 years. This creates a type of “thermostatic” backlash, in political science terminology. Both policy preferences and political participation react against policy change. No one knows if the Dobbs decision overturning Roe v. Wade will disrupt this. But it might. Despite the Democrats controlling the presidency and Congress (albeit precariously in the Senate), one of the major policy changes since Biden took office was in the conservative direction, with many states using their new discretion to pass much more conservative abortion laws. It is rare for policy to move so far against the preferences of the president’s party on such a salient topic. We don’t know how that will disrupt the normal pattern of thermostatic midterm backlash.
These two sources of uncertainty make it especially hard to predict races that are very close in the polls. Small differences in turnout and enthusiasm could determine whether there is a “polling error” in the Democrats' or Republicans’ favor. This is why Nathaniel Rakich is correct when he says that, with polls as they are, this election could plausible be a significant win for either party.