Biden wanted an early debate against Trump. Here’s how it could help or hurt him.

Former President Donald Trump wondered aloud to the crowd at Temple University on Saturday whether he should be “tough and nasty” toward President Joe Biden at the debate this week, or “nice and calm.”

Biden’s campaign has meanwhile teased hundreds of watch parties across the country and plans to roll out digital advertising around the debate, hosted by CNN Thursday night in Atlanta.

In an election year with high political stakes and low voter engagement, Biden and Trump will face off in the earliest and perhaps most consequential presidential debate in the nation’s history. After years of attacking each other, often personally, they’ll meet in person with the opportunity to define the terms of the contest, which has remained stubbornly static thus far.

“There’s been wars, criminal convictions, and we’ve seen no changes in the polling,” Emerson College pollster Spencer Kimball said. Trump and Biden are running even in Pennsylvania and nationwide. While the debate is expected to draw record viewership across the country, the target audience for both candidates will be voters in critical swing states like Pennsylvania.

“If you’re an uber Trump or Biden fan in South Carolina or Maryland, no offense but you essentially do not matter,” said Nachama Soloveichik, a GOP political consultant based in Pittsburgh.

The debate, five months before the election, comes in the midst of an unprecedented summer start to the campaign. Biden, 81, the oldest sitting president in U.S. history, is seeking momentum amid concerns about his age and ability to serve a second term. Trump, 78, was found guilty of 34 criminal charges in New York last month and will likely face questions about that conviction and his other criminal cases.

Traditionally, presidential debates haven’t started until the fall, after the candidates have been officially nominated at party conventions. Biden’s campaign suggested the earlier debate and the unique format, which involves mutable mics and no audience.

A June debate presents an opportunity for Biden to reach core Democratic constituencies that have abandoned him as he seeks reelection.

“It was smart of the Biden people to do an early debate because they have to shut down the talk about Biden’s mental acuity,” public affairs consultant Larry Ceisler said. “Biden needs to stop the bleeding with the Democratic base. The bar is so low for him, which has been set by Trump, that he should be able to meet it — if not jump over it.”

The last time the president had a highly anticipated public address was his March State of the Union address, and he was widely commended for clearly and energetically touting his accomplishments. But the debate will be unscripted, without a teleprompter, and opposite Trump, who is wildly hard to predict.

The timing, however, allows a cushion before November should Biden, who has a history of verbal slip-ups and gaffes, have some bad moments.

“Trump is just faster on his feet,” Soloveichik said. “That gives him an automatic advantage. Biden, I think is playing with the calendar to make it advantageous to him. There’s a lot of time for people to forget what happens this week. Politics in the summer, it’s the doldrums.”

But with such a long runway to the next debate in September, there’s also the chance a bad misstep or insult reverberates for months.

Trump, who repeatedly challenged Biden to debate, has since downplayed his strength, alleging the format and moderators are biased against him. His challenge will be keeping a more measured approach, a departure from his typically brash style.

“When you look at how Trump has been on the campaign trail, he has been more disciplined — relatively, for him,” Ceisler said.

The debate is also a replay of the candidates’ meetings four years ago, so viewers will be able to compare frame-to-frame how the two men sound and look. The campaigns will use the first debate to course-correct before they square off again in September.

About 10% of voters in most polls of Pennsylvania remain undecided. Most people who watch debates are there to cheer on their chosen candidate. Some voters on the fence might watch. But a lot of undecided voters just aren’t that engaged to begin with, and so might not tune in for 90 minutes.

Debates can still have an impact on undecided voters who don’t watch, as the debate content and outcome will drive media cycles and impact fundraising for campaign outreach. And while Labor Day is usually when voters start paying attention, there are several important campaign moments this summer, including Trump’s sentencing in July, his highly-anticipated running mate selection, and each party’s conventions in July and August.