CNN  — 

Ever since Tara Reade’s allegation that former Vice President Joe Biden sexually assaulted her in 1993 emerged, we’ve been waiting for hard data that provides some early signs of how the accusations – and Biden’s unequivocal denial – are playing with the public.

Now we have some – and the news should be mildly encouraging for Biden backers.

In a new Monmouth University national poll, almost 9 in 10 people (86%) said they have heard about the allegation, which is not terribly surprising, given that Biden’s denial last Friday – he said the alleged incident “never happened” – drove news coverage of the allegations made by Reade throughout the weekend.

Opinion about whether the accusation is true is very, very divided. Roughly 4 in 10 (37%) – say the allegation is “probably true” while 32% say it’s probably not true, and 31% have no opinion.

Which isn’t great news for Biden. Except that when you dig into the numbers one level further, you find this: Among the group that says the accusation against Biden is probably true, he still wins 1 in 3 of their votes. (President Donald Trump gets 59% among that group.)

What that means – at least at this relatively early stage in the general election race – is that there is a decent chunk of voters whose dislike for Trump or support for Biden overrides even their belief that Reade is telling the truth about Biden. They so want Trump out that they are supporting Biden even in spite of believing the unproven (and denied) allegation that he sexually assaulted a woman in the early 1990s.

Why? That’s harder to discern.

Maybe the allegation has less resonance with the public in the age of Trump, since more than a dozen women accused him of sexual harassment or assault in the run-up to the 2016 election (Trump has denied all of the allegations) – and a 2005 video surfaced in which he bragged about groping women – and he won anyway.

White House press secretary Kayleigh McEnany seemed to suggest last week that voters either didn’t believe the accusations against Trump or didn’t care. “You’re bringing up issues, like I said, from four years ago, that were asked and answered, and the American people had their say in the matter when they elected President Trump as President of the United States,” she said in response to a reporter’s question.

It also might be that some voters – at least the 32% of them who believe Reade’s allegation against Biden but support him over Trump anyway – simply prioritize other things over this allegation. Like the way Trump has acted in office. Or his policy positions. Or even his response to the coronavirus pandemic. Or one of a million abnormal things Trump and his administration have done while in office.

What the Monmouth numbers, more broadly speaking, seem to suggest is something old political hands have long known: Reelection races are ALWAYS a referendum on the incumbent. And to beat an incumbent, 95% of the work is in convincing people he needs to be fired while the last 5% is persuading people that you are capable of doing the job, if hired.

While Trump has defied lots (and lots) of the rules of politics, it appears as though he isn’t able to break away from this one: Voters this November will be deciding, primarily, whether or not they want four more years of him. Biden, and Reade’s allegation against him, will take a backseat to that first calculation.

And given where Trump’s poll numbers are more broadly – the Monmouth poll shows his unfavorable rating at 53% – that’s very good news for Biden.