Debates in political campaigns used to be a given. Today, candidates increasingly view them as optional — or a political liability to be avoided. Why it matters:

In a midterm cycle dominated by unprecedented spending contrast ads, the candidates themselves are remarkably reluctant to challenge each other face-to-face.

• It's a sign of how campaigns have evolved, and an erosion of norms: Candidates — fueled by their parties and super PACs — still try to tear apart the opposition, they just do it from a distance. • In the age of short, shareable video clips, TV debates offer candidates equal parts opportunity and risk: An electric moment can travel far and wide, but so can an unforced error.

By the numbers:

In 10 of the most closely watched races for governor, there are no agreed-upon debates between the major-party nominees in half of them — Arizona, Florida, Nevada, Ohio and Texas, according to an Axios review of scheduled debates. • Four years ago, just two of those 10 gubernatorial contests went without a debate.

• In 10 tight Senate races this year, there are no debates scheduled in three states — North Carolina, Ohio and Texas. That's up from one debate-free race in the same seats last time around.

• Some campaigns are still dickering over possible venues and moderators, and more debates could be added closer to the Nov. 3 election.

Driving the news:

Florida's Democratic nominee for governor, David Jolly, became the latest official no-show when he said Sunday that he wouldn't debate Republican Rep. Byron Donalds. • "I think he's acting with bad faith and continues to peddle lies," Jolly said. "You can't debate a liar." • Donalds called Jolly "scared."

• This is would be the first time since 1974 that Florida hasn't had a debate among contenders for governor. Neither Jolly not Donalds debated their primary opponents. Zoom out:

Jolly's debate dodge — unexpected for a financially outgunned Democrat running in a red state— is part of a broader pattern in which challengers and incumbents are making strategic decisions not to debate. • In some cases, they enumerate their reasons. In others, they aren't offering much of an explanation.

In Ohio Democratic gubernatorial nominee Amy Acton is refusing to debate Republican Vivek Ramaswamy, citing personal attacks against her and her family. • "I will not be giving a platform to someone who I think is not just out of touch and not right, for I think he is a danger," Acton said.

In Texas Republican Gov. Greg Abbott, who debated Democratic challenger Beto O'Rourke in 2022, hasn't agreed to debate Democratic state Rep. Gina Hinojosa this year. No explanation given.

Democratic Attorney General Aaron Ford says he's accepted two invitations to debate Republican Gov. Joe Lombardo. But Lombardo hasn't publicly committed to them — or commented about it.

Democratic Attorney General Aaron Ford says he's accepted two invitations to debate Republican Gov. Joe Lombardo. But Lombardo hasn't publicly committed to them — or commented about it. Yes, but:

One state stands out from the rest, Iowa. It had one gubernatorial debate in 2022, but has four scheduled this fall, a sign of how hotly contested the Republican-led state has become as support for Trump and his policies has cratered in farm country. The intrigue: Arizona Democratic Gov. Katie Hobbs is one of the few candidates who's declined to debate this year and also declined to debate her opponent four years ago. But she's tweaked her rationale.

• In 2022, when she faced Republican Kari Lake, Hobbs argued that Lake, a Trump loyalist, would turn a debate into a spectacle, with "constant interruptions, pointless distractions, and childish name-calling." • This year, Hobbs is refusing to debate Republican Rep. Andy Biggs, offering a new explanation: Her campaign says engaging directly with Arizonans is more effective than a debate stage built for "short soundbites and political theater."

Even the Senate — an institution built around debate — isn't immune.

• In Texas, Democratic state Rep. James Talarico has accepted invitations to three televised debates against Republican Attorney General Ken Paxton. Paxton's campaign says he'll debate Talarico but hasn't committed to any of the proposed events. (On Thursday, Talarico challenged Paxton to debate on Fox News, which he called "Ken Paxton's safe space.")

• In Texas, Democratic state Rep. James Talarico has accepted invitations to three televised debates against Republican Attorney General Ken Paxton. Paxton's campaign says he'll debate Talarico but hasn't committed to any of the proposed events. (On Thursday, Talarico challenged Paxton to debate on Fox News, which he called "Ken Paxton's safe space.")

• In North Carolina, neither former Gov. Roy Cooper (D) nor Michael Whatley, a former Republican National Committee chair, have accepted any of at least three debate invitations, although both have indicated they're open to debating.

• In Ohio, former Sen. Sherrod Brown (D) said he assumes he'll debate Republican Sen. Jon Husted, but nothing has been scheduled. What they're saying:

Brett O'Donnell, a veteran GOP debate-prep consultant, said the disappearance of debates is bad for democracy, but it's a sign of how the campaign and media landscape are changing. • "There's so much more money in campaigns now, and a way to get messages out on social media," he said.

• "There's so much more money in campaigns now, and a way to get messages out on social media," he said.

• "We live in a world where people get impatient after watching something for 15 seconds online," O'Donnell added. "How many people will actually watch an hour-long debate?"