NEW YORK — As he campaigns for president, Joe Biden’s moderate approach to governing often fails to excite his party’s most passionate voters. But on the debate stage Sunday night, as the nation wrestled with the consequences of a frightening pandemic, Biden’s pragmatism broke through in ways that affirmed why he has become the front-runner for the Democratic nomination.

The former two-term vice president and longtime senator, who has spent the last four decades as a Washington insider, faced off against Sen. Bernie Sanders and his burn-it-down progressive politics in the first one-on-one debate of the Democratic Party’s 2020 primary season.

It was Biden’s first chance to show how he might be seen in a face-off with President Donald Trump. He was crisper in his answers than he had been in forums with multiple candidates and he was more focused when framing his differences with Sanders, who used the evening as perhaps a last, best shot at slowing Biden’s march. But in the midst of an escalating global health threat, it was much more than that.

With the nation focused on the virus outbreak rather than traditions like Selection Sunday for the NCAA basketball tournament, the debate provided a national moment for Americans to more closely consider the final two men who want to be the alternative to Trump in November.

They offered dramatically different visions of leadership to an anxious nation suddenly held captive by crisis, giving Democratic primary voters, and the broader electorate, a chance to take an up-close measure.

Biden and Sanders faced each other from lecterns strategically placed six feet apart in line with the recommendations of health experts. A live audience was barred from attending. They did not shake hands. The dynamic was far different than the forums of six or more candidates, narrowcasting the choices.

It was a moment seemingly made for someone with extensive governing experience. And if nothing else, Biden has that.

He leaned hard on his experience as vice president, and how he worked in other times of national crisis, something that Sanders simply could not do.

Demonstrating a command of the tools available to the federal government in crises, Biden said he would mobilize the military to strengthen the health care system’s capacity in the short term. He repeatedly cited his experience in the White House situation room, where he and the Obama administration contained an Ebola threat and helped avoid a global economic collapse.

“People are looking for results, not a revolution,” Biden charged, repeating a familiar attack against Sanders that seemed to carry new weight as millions of home-bound Americans watched. He added: “We have problems we need to solve now.”

The stakes had never been higher for Sanders, who is undoubtedly on the path to losing the presidential nomination for a second consecutive campaign. The Vermont senator has fallen behind Biden in the delegate hunt, and he’s bracing for another bad primary night Tuesday when Arizona, Florida, Illinois and Ohio weigh in.

Already, he’s under pressure from the Democratic establishment to drop out.

Sanders, an experienced debater by now, outlined his own plan for combating coronavirus, which included a call to increase the number of ventilators and intensive care units at hospitals. But he also did what he has done for his long political career: He pivoted to his broader concerns about the nation’s health care and economic systems and tried to frame the current crisis as further proof of the need for his signature Medicare for All plan.

His consistency is often his strength, yet in an election transformed by an unexpected pandemic, that consistency has its limits.

Discussing the ongoing health threat at one point, Sanders declared: “It is time to ask the question of where the power is in America. Who owns the media? Who owns the economy?”

Yet many voters are focused on the immediate health and safety of their loved ones. And they’re looking for political leaders for reassurance and decisive action.

Polls do suggest that Sanders’ plans to transform health care and income inequality are popular. Yet, they are not necessarily seen as realistic.

For his part, Biden showed flashes of the fighting spirit that first signaled his presidential mettle when he sought the White House the first time, more than 30 years ago.

He put Sanders on the defensive repeatedly, including for favorable comments the senator had made about authoritarian regimes in Cuba and other Latin American countries. And he defiantly beat back attacks against his own record on the 2008 economic bailout, his support for the Iraq War, and his past willingness to cut Social Security as part of a deficit-reduction package.

Yet the night will be most likely remembered for a virus that has suddenly turned American politics, and American life, upside down, and in the process, may have driven voters even closer to the candidate who represented far more experience and far less risk.

“This is a crisis,” Biden said. “We’re at war with a virus.”