As President Trump dodges the GOP debates and speculation mounts that President Biden and Mr. Trump — or another GOP contender — may not debate in 2024 at all, second-tier Republican presidential candidates and potential 2028 Democratic contenders are finding alternative venues to make their voices heard. Will this become a new trend?

On Wednesday in New Hampshire, the formula got its first test. A GOP presidential hopeful, Vivek Ramaswamy, and a Democratic congressman, Ro Khanna, took to the stage at the New Hampshire Institute of Politics at Manchester for a one-hour substantive debate on the economy, foreign policy, climate change, and government reform.

“Civil” was the key word thrown around by both candidates, who disagreed on much but kept the conversation friendly and on topic. The moderator promised “no political horse race questions” and no mentions of Mr. Trump.  

“Why can’t we do this in living rooms across America, where you can have a civil conversation with someone you disagree with?” Mr. Khanna said at the start of the debate, calling “our deep polarization” the biggest issue facing America.

“I am a free speech absolutist and advocate,” Mr. Ramaswamy tells the Sun. “The more the better. More speech is good.”

At the end of the month, another of these unofficial debates will test the formula again. The Florida governor and Republican presidential candidate, Ron DeSantis, is scheduled to debate California’s governor, Gavin Newsom, on Fox News. Mr. Newsom is an expected 2028 Democratic presidential contender, and many are speculating that if Mr. Biden were to drop out of the race, Mr. Newsom would be his natural replacement.

The idea for the Ramaswamy-Khanna debate was spawned on social media — a rare instance of a public spat turning into positive, real-world dialog. Another Republican presidential candidate, Chris Christie, the former New Jersey governor, posted to X that he was “very disappointed” that the Republican National Committee was forbidding him and Mr. Ramaswamy from debating each other on Fox News.

“Voters need more information, not less,” Mr. Christie posted. “I’m always up for discussions. It’s a shame the RNC and Donald Trump aren’t.”

Mr. Ramaswamy replied, “The RNC won’t let the GOP candidates do it, but I’d go for it with a smart Democrat who’s willing.”

Mr. Khanna, a member of the Congressional Progressive Caucus and a surrogate for Mr. Biden, who is not campaigning in New Hampshire and will not be on the state’s primary ballot, took the bait. Mr. Khanna has campaigned extensively in New Hampshire and other early-voting states, leading to speculation he has larger political ambitions.

Messrs. Ramaswamy and Khanna are both Indian American and have ties to the tech industry, but their political views diverge widely. On the economy, Mr. Ramaswamy stressed the importance of more oil drilling and of slashing the administrative state. 

Mr. Khanna touted what he calls the Biden administration’s “success” on the economy, and criticized Republicans for always calling to slash taxes and deregulate. He called Mr. Ramaswamy’s plan to cut 75 percent of Washington’s bureaucrats a “horrible idea.” 

Foreign policy is where these two men’s differences were most pronounced. Mr. Khanna described the bumper sticker for his foreign policy agenda as “responsible engagement.” Mr. Ramaswamy said his is “American interests.”

Both men condemned the October 7 Hamas attacks in Israel, but Mr. Ramaswamy warned against American military engagement in the Middle East.

“We need a commander in chief who is expressly committed to keeping us out of World War III,” he said. “We have to confront the reality that every time we stick our nose in the Middle East it’s like somebody waddling into a glass shop — we think we’re helping — it’s a bull in a china shop. We make things worse. We leave a mess behind.”

Mr. Ramaswamy added, “My view is that Israel has an absolute right to its own national self-defense.”

“I don’t want to be like Nikki Haley and just put you down in some way, because I didn’t think that was fair,” Mr. Khanna said, suggesting that Mr. Ramaswamy get a briefing from the CIA director before forming his foreign policy. “Why do you have such an impoverished vision of America?” he asked.

“I don’t bow the knee to the experts,” Mr. Ramaswamy replied, saying that a president needs to be “purposely skeptical” of the “expert class.”

“American interest requires American leadership,” Mr. Khanna said. 

The one area the men did agree on was the need for government reform and to get political action committee money out of politics. They also agreed on the importance of more — not less — speech and across-the-aisle discussions.

“I think it’s healthy for democracy to have multiple engagements like this,” Mr. Khanna tells the Sun. “We need more of this in this country.”

When asked whether he thought Messrs. DeSantis and Newsom would follow their lead and have a civil, substantive debate, Mr. Khanna demurred. “Maybe we’ve set the tone. We’ll see if they follow,” he said.