If Vice President Kamala Harris manages to win this election, it will be because Donald J. Trump and his political team made the most calamitous mistake in the history of presidential politics: agreeing to the June presidential debate. At first glance, that statement might seem counterintuitive. After all, wasn’t that early presidential debate a gigantic disaster for Democrats, forcing them to first spend a month debating what to do about President Biden before finally convincing him to drop out in favor of Harris? That’s certainly been the prevailing narrative from the national media.

In fact, however, the opposite is true: Trump would have had a much easier race against Biden than Harris, and probably was well positioned to win. That’s readily apparent because it’s exactly why Biden and his team pushed for the early debate: they hoped to recover a bit of momentum from a strong performance. Trump was already leading, by various margins, in nearly all public polling since last October. Before the debate, it was about a one-point lead; by the time Biden withdrew, it had grown to a three-point lead.

At the time Trump agreed to the early debate, there was reason to question the wisdom of that decision. For one, Trump gave the Democrats nearly everything they wanted in terms of the debate schedule and format. That’s not a strong position, especially for a candidate ahead who likes to portray himself as a brilliant dealmaker. There are a couple of possible lines of reasoning for why Trump’s team went along with the Democrats in the debates.

They may have reasoned that a strong performance in the early debate would have severely weakened Biden. They probably didn’t even consider the possibility that Biden would drop out – and if they did, they probably considered Harris the weaker candidate. Those are both reasonable assumptions since no presidential candidate had ever dropped a reelection bid at this late a date before. If they did consider Harris as a candidate, it’s reasonable for them to presume they’d be able to frame her as a San Francisco liberal. They also probably didn’t think she’d be a strong candidate herself, since her first presidential run – much like Biden’s earlier efforts – was a complete disaster. While that’s good logic, on both counts they proved to be entirely wrong, mainly because they didn’t consider one factor: just how united Democrats are in their loathing of Trump.

It’s interesting to consider how things would have gone if the campaigns had followed the traditional debate schedule. Then, if Biden had an equally poor performance as he did in the June debate, it would have been in late September. He wouldn’t have had time to hem and haw for a month about dropping out. Even if he’d had two brilliant debates following that disaster, it might have been too little, too late – or it could have saved his candidacy. Either outcome would be better for Trump, since he’d still have ended up facing Biden, with a divided Democratic Party that was less than enthusiastic about him.

While we don’t know what the state of the race would have been without that June debate, it seemed to be trending in Trump’s favor. Now, perhaps their internal polls painted a less rosy picture than the public ones, convincing Trump’s team that he, too, benefited from an early debate. We won’t know the inside story of that for years, if ever, but it wouldn’t be the first time that internal polls differed substantially from public ones.

After the first debate, the Trump team continued to make poor decisions, agreeing to go ahead with the scheduled second debate. The debate schedule was an agreement between the Trump and Biden campaigns, not the parties. With a different opponent, Trump could have demanded changes to the format or moderators, but he didn’t. Instead, he again went along with the Democrats’ plan and proceeded to turn in a less-than-stellar performance.

If Trump loses this election, it will be because of the debates: he agreed to the early debate, allowing Democrats time to change candidates, and then failed to deliver a knockout blow against their replacement. Typically, debates aren’t that consequential, because there are a number of them right before an election, giving candidates time to recover – like Obama did after his first poor debate performance against Mitt Romney. This year, though, they proved enormously consequential, just not quite in the way that most people probably think.