Vivek Ramaswamy and Ro Khanna Debate in New Hampshire

Vivek Ramaswamy, a Republican presidential candidate, and Ro Khanna, a Democratic member of the House, squared off on Wednesday in New Hampshire in what was billed as a civil discussion between two Indian Americans over the future of the United States.

But over the course of an hour at Saint Anselm College in Manchester, N.H., Mr. Ramaswamy repeatedly slipped into his stump speech on the “black hole” in America’s collective heart and his belief that the nation was not, as he once thought, the declining Roman Empire, while Mr. Khanna struggled to talk up the record of President Biden against his opponent’s blizzard of words.

“It is, I think, regrettable to be carrying the water of Joe Biden when the fact that everyday Americans know they’re suffering at the hands of policies that came from this administration,” Mr. Ramaswamy snapped back.

The appearance of Mr. Khanna, a California Democrat, on a stage in New Hampshire — the second time this year for him — was a testament to the frustrations that he has said he feels about how Mr. Biden and other Democrats have ceded ground to Republicans on putting forth an economic vision. The meeting was initially to be a conversation on race and identity at the University of Chicago, but when Mr. Ramaswamy backed out, Mr. Khanna challenged him on social media — and chased him to the first Republican primary state.

On Nov. 30, Gov. Gavin Newsom of California, who has tried to extend the White House’s message to audiences he does not believe it’s reaching, will debate Gov. Ron DeSantis of Florida on Fox News.

In the end, the Saint Anselm meeting was largely a showcase for Mr. Ramaswamy to try to rescue a flagging campaign, which has slipped to fourth place in polling averages in the state, behind Mr. DeSantis, Chris Christie, the former New Jersey governor, and Nikki Haley, the former South Carolina governor who has surged into second. All of them are well behind the front-runner, Donald J. Trump.

Mr. Ramaswamy demonstrated that his dogged “America First” isolationism has not been jarred by the bloody conflict between Israel and Hamas. At one point, he declared, “I could care less about leading in the Middle East,” saying of Israel, “Let’s get out and let our true ally defend itself.”

To that, Mr. Khanna asked: “Why do you have such an impoverished vision of America that the only thing America is going to have is a provincial sense of its own interest?”

Mr. Ramaswamy also showed his propensity to not allow the facts to get in the way of his views. When Mr. Khanna boasted of the 13 million jobs that have been created under Mr. Biden, his opponent cautioned that the government was “the sector with by far the greatest growth in jobs.”

While it is true that in recent months the government sector has shown signs of recovery, government employment, as of last month, remained below its prepandemic level by 9,000 jobs, while the private sector has now recovered all the jobs lost in the pandemic and then some.

Mr. Khanna has been outspoken in challenging his party and his president to get more aggressive in sharing a vision for more inclusive economic growth. He tried again Wednesday, talking up government investment to rebuild manufacturing: “For the Republicans, and I see some of this in what you’ve adopted, they see any problem, and they say let’s cut taxes, let’s deregulate,” Mr. Khanna said. “How is that putting a steel plant up in Johnstown, Pennsylvania?”

But he largely missed the opportunity to highlight Mr. Biden’s biggest legislative achievements in industrial policy, which got only glancing references: a $1 trillion infrastructure bill, a $280 billion measure to rekindle a domestic semiconductor industry and the Inflation Reduction Act, with its spending to combat climate change.

Meantime, Mr. Ramaswamy’s well-worn talking points dismissing the threat of climate change, calling for eliminating three quarters of the federal government, and cutting education spending largely went unchallenged.