It's always interesting in a Presidential election year that people treat the Presidency as the most important office, and analyze the U.S. election entirely in terms of it. It's true that the Office of the President is the single most powerful office held by an individual, and that a strong Presidential candidate can boost candidates of the same party (and vice versa), but the most important result of Election Day is the new disposition of Congress. 2024 was a very bad election year for the Democrats, and it was not the election of Trump but the fact that they have certainly lost the Senate (which was mostly expected) and it is (at this point) very likely that they have lost the House. They had better hope for the as-yet-indeterminate House elections to break unexpectedly Democratic, because that is the only thing that would prevent the night being an entire disaster from them. (Even if the unexpected happen, the best they seem to be able to hope for is an unstable bare majority.) To lose one of the Presidency, the Senate, or the House is a misfortune; to lose all three in a single election is a sign of carelessness.
Here in Texas one of the primary issues, without any doubt, was border control. I noted years ago here that, whatever one's personal preferences on immigration, the actual infrastructure in Texas for providing necessary and useful services to immigrants was already being strained to the breaking point, as, for instance, refugee services were struggling with the problem of what to do when they ran through their entire year's budget in a matter of months. We have long since passed the breaking point, with no repair at all in sight. It has been interesting over the past eight years to see Democratic candidates swing from being fairly negative on border control, to carefully neutral, to this year's continual, desperate attempts to convince people that they would be stricter on border control than the Republicans. Over and over one would see political ads by Democrats highlighting the issue as their primary issue. None of it would move Republicans, of course, but that was very clearly not the purpose of many of the ads; they were attempts to convince independents and Democrats that they would solve the problem. But it was all futile; no one really thought that the candidates had the backing of the White House or the Harris campaign on the point, and there wasn't much reason for thinking that once in office the candidates would break heavily against their own party on it.
Just from what one hears, it seems like this was a common problem for Democratic candidates across the board; the particular issues would differ from state to state, but one repeatedly gets a sense from their political strategies that many of them felt that they were set up by Biden and Harris to fail, or, at least, that they were struggling to make headway in relative isolation. And again, to lose the Presidency is to lose a very powerful office; to lose Congress is to lose the most powerful political force in the entire world.
In any case, as people have to keep being reminded, this is only the first phase for the Presidential election; Trump's margin is comfortable enough that he is practically guaranteed to win, but the actual election has just begun. December 11 is the deadline for the states to submit their Certificates of Ascertainment, which establish the Electors; the Electoral College will meet on December 17 actually to elect the President; they will submit their Certificates of Vote by December 25; and then Congress will count and confirm the votes on January 6.
