John Fetterman and Mehmet Oz are finally facing off in a Senate debate. Here’s what we’re watching for.

Debates can be an exciting, unfiltered look at the candidates, but this year might be the most intense matchup in recent Senate history, given John Fetterman’s stroke and the intense focus on his health.

Mehmet Oz, a cardiothoracic surgeon, has suggested Fetterman’s not up to the job of senator and also hasn’t been transparent about his condition. Fetterman, who has ramped up public events and the length of his stump speech in recent weeks, has said he’s fully capable of serving.

With just one debate (Fetterman insisted on a single event), it’ll be the first and only time many voters get to see both candidates speak outside of a TV ad. And it’ll be the only major debate of a massive campaign season in Pennsylvania, because Josh Shapiro and Doug Mastriano don’t have any scheduled in the governor’s race.

First some basics:

The one-hour debate will air on Tuesday at 8 p.m. on TV stations across 62 counties statewide. It will also be livestreamed. Oz and Fetterman will debate from abc27 studios in Harrisburg. Radio stations will also have free access to air it.

It will be moderated by WHTM abc27 News anchor Dennis Owens and WPXI anchor Lisa Sylvester.

Fetterman’s recovery from his stroke has become a national focus. He has done a number of interviews, many of them televised, but this will be the first and maybe only opportunity for voters to see him in an extended exchange, with no edits. He still has some problems processing speech, but he and his doctor say his cognition is fine. Aside from the substance of his answers, it’s a chance to show voters he’s well enough to do the job.

He clearly knows people are paying attention: On Wednesday, he released his latest doctor’s note. Julia had the scoop and the details. There are perils for Fetterman if he stumbles, but also risks for Oz, who could come across as cruel and insensitive if he attacks Fetterman over his health.

» READ MORE: ‘It’s ... going to be a challenge’: Fetterman downplays Pa. Senate debate expectations with Oz

“You have to be really careful about how you handle that, particularly as a physician,” said Berwood Yost, of Franklin and Marshall College.

He noted that about half of Pennsylvania adults have a chronic health condition. “More people are like John Fetterman in terms of their health, dealing with some kind of health condition, than they are like Dr. Oz, who seems to be perfectly fit.”

Fetterman will use closed captions at the debate, as he has for all of his one-on-one media interviews, to ensure he understands the questions amid his auditory processing challenges. That means there will be a slight delay between the moment the moderator asks a question and when Fetterman answers it. Viewers will be told at the top of the debate that Fetterman’s using the technology.

What we don’t know is how that system will impact the back and forth you typically see at a debate. How much will the candidates address each other?

Oz is a polished daytime TV host who knows his camera angles and how to craft TV moments, but one of his biggest challenges has been proving he’s also a relatable Pennsylvanian.

We’re looking to see how the ultra-wealthy celeb tries to carve out some down-to-earth moments to drive home that a real person is under the TV gloss.

» READ MORE: Oz has run a campaign largely against Fetterman. Now he has a chance to tell voters what he’s for.

Even before his stroke, Fetterman wasn’t great at debates. He was visibly grouchy during the Senate primary debates and at one point bristled, asked to explain a basic piece of his policy (at what income level would he raise taxes?).

He has campaigned more on an ethos — “the union way of life” and “forgotten communities” — than wonky ideas. At times he can be expansive and make thoughtful arguments about his principles. At others, he’s gruff and seems miffed by the notion that he should have to explain himself at all.

Which Fetterman shows up on the biggest stage of his political career?

Throughout his campaign, Oz has evaded several key policy questions related to guns, abortion rights, and the minimum wage.

Look for Fetterman to ask him again and again where he stands on Sen. Lindsey Graham’s bill that would ban abortion at 15 weeks. Most of Oz’s campaign has been about what he’s against: Fetterman, Joe Biden, Democrats, crime.

This debate could press him to explain what he’s actually in favor of. What’s his vision as a senator?

Fetterman on crime, Oz on abortion: Fetterman has faced a barrage of attack ads over his record on crime. Oz has been deluged by questions about his opposition to nearly all abortions.

How do they respond on the fly, when their opponents will be picking through their records? Do either have good, concise answers for the issues weighing on their candidacies?

Sources we talk to think it will have more of an impact than debates usually do in these races, but how much is unclear.

“One of Fetterman’s major selling points (fair or not) was his massive size and strength. … Articulation is not as important as strength, and if he appears weak compared to Oz, who is about half his size, then he’s in a world of trouble,” said Shippensburg political science professor Alison Dagnes

“I’d argue this debate probably means more to this race than it has for any Senate race for the last 30 years,” said Matt Beynon, a Republican strategist.

Beynon argues candidates don’t tend to win races in a debate, but they can lose them.

“I think with this one, a lot of folks can relate to someone going through a serious health problem … and it’s not mean, but it’s just a demanding job, and they’ll be looking for, ‘Can you stand up there and do the job?’”

That’s assuming those key undecided voters pay attention, though. 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 heavily engaged to begin with, and so might not tune in for an hour on a Tuesday night.

“I’m not sure even a debate performance can move independent people — if there are any of those people left,” Democratic strategist Mustafa Rashed said. “Is there anyone out there really trying to decide between the two of them?”

» READ MORE: It’s the nation’s most expensive Senate race. We dig into where Fetterman’s and Oz’s money comes from.

It’s more likely, Rashed argued, that people are deciding whether to vote for a candidate or sit the race out, which could matter in a tight race.

Still, even if people don’t watch, we know that viral moments or political face-plants can take on a life of their own, especially in this race.

A version of this article appeared in our PA 2022 Election Newsletter. Sign up to get the newsletter delivered directly to your inbox.