(NewsNation) — All eyes are on Pennsylvania as the two nominees for U.S. Senate — Republican Dr. Mehmet Oz and Democrat John Fetterman — prepare to square off in their first and only debate Tuesday.

The phrase “first and only” has become an increasingly common descriptor of this year’s debates and there’s evidence to suggest the traditional format — wherein candidates stand on a stage and exchange ideas — may be a thing of the past.

As recently as 2010, there were 17 debates across the five most competitive Senate races, according to Brookings. This year, just six have been scheduled or have already taken place as of Oct. 10.

NewsNation will air the primetime debate exclusively with pre-debate analysis provided by Leland Vittert during a special edition of his show “On Balance” from 7-8 p.m. ET, followed by the full debate from 8-9 p.m ET. Here’s how to watch.

That scarcity means Tuesday’s showdown could end up weighing more heavily on the minds of voters. Pennsylvanians NewsNation spoke to are particularly interested to see how Fetterman performs, given his recent health issues stemming from a stroke back in May.

After trailing for the last few months, Oz has closed the gap in recent weeks and now has a 48% chance of winning the race — up from 30% less than two weeks ago — according to Decision Desk HQ.

Earlier this month, the two major Senate candidates in Georgia traded barbs in their first and only debate. Republican candidate Herschel Walker declined an invitation to a second debate hosted by the Atlanta Press Club, leaving incumbent Democratic Sen. Raphael Warnock to discuss the issues with Libertarian Chase Oliver.

Candidates in other races have avoided the debate stage altogether. Just two weeks before Election Day, the top candidates in Nevada’s hotly contested Senate race have yet to debate and don’t intend to. Both campaigns have claimed it’s the other side’s fault, according to NBC.

Gubernatorial hopefuls in both major political parties have dodged debates.

In Arizona, Democrat Katie Hobbs has refused to debate her Republican opponent Kari Lake, a former TV news anchor.

Hobbs, who currently serves as the Secretary of State, has said she doesn’t want to give a platform to her opponent’s “lies.” Lake has repeatedly called into question the legitimacy of the 2020 election despite no evidence of widespread voter fraud.

In Ohio, Republican incumbent Gov. Mike DeWine has declined invitations to debate his Democratic challenger Nan Whaley.

Back in Pennsylvania, the GOP candidate for governor Doug Mastriano and Democrat Josh Shapiro have not been able to agree on debate terms.

Even presidential debates could be in jeopardy.

Earlier this year, the Republican National Committee unanimously voted to withdraw from the Commission on Presidential Debates (CPD), citing bias against GOP candidates as its primary reason.

“To be clear: we are not walking away from debates. We are walking away from the CPD,” a statement from the RNC read.

But perhaps the broader move away from debates shouldn’t come as a surprise. With the power of social media, candidates can reach voters more directly than ever before, and research suggests they may have little to gain from the time-honored format.

Studies show televised debates have little to no impact on the decisions of individual voters.

What impact they do have may come from candidates’ mistakes, rather than their successes.

“There is no guarantee…that a winning debate performance carries a benefit,” Colby Galliher, a research analyst at Brookings, wrote. “A flop, on the other hand, is likely to hurt the loser.”

In a September 2021 debate, Virginia’s Democratic candidate for governor Terry McAuliffe defended his decision to veto a bill that would have required schools to notify parents of books with sexually explicit material, by saying, in part: “I don’t think parents should be telling schools what they should teach.”

McAuliffe’s GOP opponent, now-Gov. Glenn Youngkin, seized the opportunity and campaigned on the remark.

Weeks later, Youngkin would go on to defeat McAuliffe in the election.

Exit polling showed 84% of voters felt parents should have at least “some say” in what their child’s school teaches — more than half of those surveyed thought parents should have “a lot” of say.