Sixty years after Kennedy vs. Nixon made presidential debates a television sensation, voters can no longer take them for granted.

Why it matters: There have been general election debates during every presidential cycle since 1976, but the debates' status as a hallmark of the election process may be in trouble.

• "I'm afraid we may be to a point where we're going to see the demise of our presidential debates," said Mitchell McKinney, professor of political communication at the University of Akron in Ohio.

Driving the news: Three general election presidential debates have been scheduled for 2024, but it's not clear whether they will happen.

• The Republican National Committee has said that the eventual GOP nominee can't participate in debates hosted and organized by the independent Commission on Presidential Debates.
• President Biden, the prohibitive Democratic nominee, has not yet committed to participating, while former President Trump, the Republican front-runner, has skipped every primary debate this cycle.
• "I think that there is the greatest chance that we've had since debates resumed ... to not have debates featured as part of our general election campaign," McKinney said.

Between the lines: Some Biden campaign staffers are also still upset over the 2020 election debates, when the Commission on Presidential Debates allowed the Trump campaign to flout some of its rules over debate protocols and COVID-19 precautions.

• Trump could still participate in a general election debate, as he never signed the pledge vowing to only participate in RNC-sanctioned debates.

Zoom in: Republican primary debates may also be finished for the remainder of the 2024 cycle, as former U.N. Ambassador Nikki Haley said this month that she would not participate in a debate unless Trump or Biden also show up.

• ABC News and CNN had to cancel their debates planned ahead of the New Hampshire primary after only Florida Gov. Ron DeSantis had accepted the invitation to appear on stage.

The big picture: Trump is not the first presidential candidate to skip a debate.

• Richard Nixon sat out of the debates in 1968 and 1972, and Jimmy Carter skipped the first of two debates against his GOP challenger Ronald Reagan in 1980.
• There were no debates from 1960 to 1976, but there have been at least two debates during every cycle since they resumed.

State of play: Debates bring the risk of attacks from opponents or a gaffe or stumble, which for a front-runner could do more harm than good.

• "When you're 40 points up ... why would I let these people take shots at me?" Trump said over the summer.
• While his GOP rivals have scrapped on stage, Trump has sat for counterprogramming events that featured friendlier hosts and more forgiving audiences.
• Trump cruised to victory at the Iowa caucuses, where most voters said they didn't care if he participated in a primary debate, and he continues to dominate primary polling.

Primary debates were once an important way for candidates to get in front of voters, but viewership numbers from the 2024 cycle show their dwindling influence.

• The fifth Republican primary debate this month drew just 2.5 million viewers, while Trump's competing town hall averaged 4.3 million viewers.

What to watch: The proliferation of other platforms, including social media, has made it easier for candidates to skip the debates and still get in front of voters on the candidates' own terms.

• During the 2020 presidential election, one of the three planned general election debates was canceled after Trump refused to participate in a virtual format due to COVID-19. The candidates instead sat for competing town halls.
• "The substitute is candidates able to maneuver their own political program, political show," McKinney said.
• "Everyone can go to their own person's town hall and cheer on their own person," he said.

Go deeper: ABC News cancels New Hampshire debate