Sometimes my predictions match those of people who think this or that issue makes a bigger difference than it does. Sometimes they don't. But what's important to understand here is that a small percentage of voters (in some cases even a fraction of 1%) who are extremely motivated to vote in a particular way, or for that matter at all can decide those close races.
This year, abortion seems to have had a bigger impact than I expected, but not much bigger. Polls saying that X% of likely voters consider it a top issue tend to obscure the fact that most of that X%, being likely voters, were already going to vote, and that they were probably going to vote for the candidates they voted for anyway. What changed outcomes was the much smaller percentage of voters who bothered to vote when they might not have otherwise, or whose sentiments on that one issue were opposite the way they usually vote. That is, the marginal voters.
So, let's talk about Donald Trump. Every time, and nearly everywhere, an election turns into a referendum on Donald Trump, Donald Trump's party loses races it would otherwise have won.
The 2016 presidential election was a referendum on Barack Obama, on the Democratic Party, and most of all on Hillary Clinton, which is why he won. But Republicans lost congressional seats in 2018, lost the presidency in 2020, and saw a "red tsunami" shrink to a "red trickle" in 2022, because Democrats, Trumpists, and Trump himself were able to turn those elections into referendums on Trump.
This year, just like in 2018 and 2020, many partisan Republicans, and not a few analysts, are 1) calling for the GOP to "move on from Trump," and 2) talking themselves into believing that it can do so.
That whole idea ignores the big impact Trump is going to continue to have at the margins.
Even if most Republicans "move on from" Trump, some are never going to (there are still Republicans claiming that Nixon was great and just got screwed).
As often, I'm just going to throw out a number with no evidence to back it up, because we're talking hypotheticals here.
Let's just suppose that a measly 10% of the Republican base of "likely voters" is going to remain Trumpy for the foreseeable future, and that they're going to remain particularly motivated to vote, campaign, and run for office, as the Trump base has continued to be.
Ten percent is not enough to win a Republican primary or a general election.
But it's enough to change the outcome of a Republican primary or a general election that's closer than 9.999x%.
For the foreseeable future, Trumpist candidates will continue to contest Republican primaries and (often with a "boost" from Democrats) win some of those primaries -- the ones that are close races, anyway, because if even 1/10th of that 10% turns out, that's a 1% edge right there.
And for the foreseeable future, Democrats will turn close general elections featuring Trumpist GOP candidates into referendums on Trump.
Trump is going to be a gift that keeps on giving to the Democrats for some time now. That's true even if he doesn't run for president in 2024. It's true even if he goes to jail or keels over and dies from a heart attack or stroke. It's even true if he makes a speech about how completely wrong and bad he's been and urges Republicans to forget him (this year in Pennsylvania, much of his own voter base supported the "Trumpier" candidate for US Senate in Pennsylvania even though he had endorsed someone else -- and his endorsement of the primary winner, Mehmet Oz, probably made the difference for Democrat John Fetterman).
It's not necessary that 51% of Republicans to be Trumpy for elections to continue being referendums on Trump to the detriment of the GOP. A handful will do. The margins are important.