Ron DeSantis began the 2024 campaign as a formidable candidate, with early poll numbers that rivaled or even exceeded the likes of Ronald Reagan and Barack Obama.

In the end, that early strength meant only that he had more room to fall.

There are countless reasons Mr. DeSantis fell apart and ultimately ended his campaign Sunday — including that his opponent proved once again to be a juggernaut. Perhaps Mr. DeSantis might have won the nomination in most other years, if he hadn’t been going against a former president.

But rather than dwell on his losing campaign, it’s worth returning to his apparent strength at the outset — that brief moment when Mr. DeSantis, or at least the idea of Mr. DeSantis, routinely led Mr. Trump in high-quality head-to-head polls.

In the eight years since Donald J. Trump won the Republican nomination, this was the only moment when Republican voters appeared willing to go a different direction. Mr. DeSantis didn’t capitalize on the moment, but nonetheless it’s the only glimpse we’ve had into the post-Trump Republican Party. We saw something that might bring it about, and we saw what it might look like.

Over the last eight years, Mr. Trump has said and done countless things that might have doomed any other politician. He’s been impeached twice. He encouraged what turned into the Jan. 6 riot. He’s been charged with multiple federal crimes. None of it really made any difference in his support.

That is, until November 2022. The disappointing Republican showing in the midterms damaged Mr. Trump in the polls, and Mr. DeSantis surged to take a clear lead in head-to-head polls that lasted for months.

Before the 2022 midterm elections, it would have been hard to predict that this would be the event putting Mr. Trump at a disadvantage. But it was, and it’s worth noting at least a few things that may have helped make the post-midterm period different:

  • The attacks weren’t coming from liberals — but from conservative elites and conservative media.

  • The midterms made Mr. Trump look weak and like a loser. Unlike in the 2020 election, Republicans conceded their defeats. Mr. Trump himself acknowledged that the midterms were disappointing. This time, there were no alternative facts.

  • The midterms allowed Mr. DeSantis, who won in a landslide, to contrast favorably with Mr. Trump without needing to directly engage or attack him.

We’ll never know what might have happened if Mr. DeSantis had acted quickly to exploit the opportunity. Instead, he waited months to announce his candidacy.

What we know is that these favorable conditions didn’t last long. In late January, Mr. Trump went on offense against Mr. DeSantis, and he didn’t punch back. Now it was Mr. DeSantis, not Mr. Trump, who looked weak. Instead, the punches coming at Mr. Trump started arriving from the criminal justice system, not from the right. Conservatives rallied to his defense, as they have time and again.

The wagons had been circled by the time Mr. DeSantis started attacking Mr. Trump over the summer.

Mr. Trump triumphed in the 2016 primary in no small part because his opposition was divided.

To his right, there were the orthodox conservatives, like Ted Cruz, who saw Mr. Trump as a big government spender and social liberal. On his left, there were the moderate-establishment types such as Jeb Bush and Marco Rubio, who opposed Mr. Trump on foreign policy, trade and immigration. Together, the two factions had the numbers to beat Mr. Trump, but their deep divisions were irreconcilable.

But at the end of the 2022 campaign, Mr. DeSantis briefly held the promise of uniting the moderate and conservative opposition to Mr. Trump around a new set of issues: the coronavirus response and the “woke” left.

It might seem strange to think that these conservative issues might help Mr. DeSantis with moderates, but they were being fought well to the left of the old 1960s culture wars. Conservative donors were every bit as opposed to D.E.I. initiatives as the party’s base. In many cases, these conservative causes found qualified support from liberals in defense of free speech on campus, opposition to school shutdowns, skepticism on trans issues, support for colorblindness and merit-based education, and more.

What all of these issues had in common was that the left, especially the academic left, had pushed far enough to trigger a backlash. And more than any other politician, Mr. DeSantis was the conservative politician who rose with that backlash against “woke” and coronavirus restrictions. The broad range of anti-woke and anti-pandemic politics meant that there were many moderates and conservatives who thought they agreed with Mr. DeSantis. They imagined him as a politician much like themselves, much in the same way that both antiwar progressives and centrist Democrats saw themselves in Mr. Obama in 2008.

It wasn’t so. The coalition behind the imagined Mr. DeSantis crumbled.

The new issues did not do the trick for him:

  • They lost their punch. The pandemic ended. “Woke” steadily faded from the news. The uproar over critical race theory vanished. More traditional issues, including abortion and the border, became more salient.

  • The issues did not offer a clear contrast with Mr. Trump, who could hardly be derided as “woke” and wasn’t exactly remembered for his support of Covid-related restrictions.

  • The issues dragged Mr. DeSantis into the world of the way-too-online right, leaving his speeches riddled with arcane acronyms like ESG and deprived of any coherent, overarching message.

Worse, Mr. DeSantis campaigned as if he were entirely unaware of the delicate balancing act of coalitions necessary to defeat Mr. Trump. It’s hard to imagine he wasn’t aware — it’s exactly what bedeviled Mr. Trump’s opponents eight years ago. Yet a key super PAC supporting Mr. DeSantis brought on Jeff Roe, the consultant behind Mr. Cruz’s losing 2016 campaign. And Mr. DeSantis never seemed to throw a bone to the establishment Republican wing of the party. He couldn’t even be acceptable to moderates on Ukraine, a favorite issue of the neoconservatives who inevitably had to play a role in any anti-Trump coalition.

Instead, Mr. DeSantis offered barely any contrast with Mr. Trump on the issues. The strategy, sometimes known as “Trumpism without Trump,” supposed that Republican voters were ready to move on from Mr. Trump personally, even though they supported his views on the issues. Needless to say, that proved to be wrong. At the same time, his consistently conservative views on the issues alienated moderates and culminated in the rise of Nikki Haley.

Mr. DeSantis would have struggled to maintain an ideologically diverse anti-Trump coalition, even if he had been every bit as deft as Mr. Obama was in his 2008 victory over Hillary Clinton. The fight against “woke” was no Iraq War. National security, abortion, entitlements and other issues still divide Republicans, just as they did in 2016.

But for a glimpse of what a successful alternative to Trumpism might look like one day, the imagined DeSantis of the outset of the campaign is a good place to start. The backlash against the woke left may have petered out, but it’s a reminder that campaigning against the excesses of the left has the potential to unite the right while appealing to a sliver of disaffected moderates or even liberals. If these or other new issues overwhelm the old ones, suddenly there might be an opening for conservative politics to look very different.