WILMINGTON — Joe Biden’s nostalgic talk about experience, stability, and order doesn’t make for the most thrilling campaign platform. But amid a global health crisis, it may suddenly find new relevance.

As the coronavirus and its disruption spread, Biden tried to strike a contrast with President Donald Trump here Thursday, somberly speaking before American flags in an image staged to present him as an alternative national leader in a moment of uncertainty.

“When I’m president, we will be better prepared, respond better and recover better," Biden said. "We’ll lead with science, we’ll listen to experts, we’ll heed their advice and build American leadership. And I’ll always tell you the truth.”

Biden expressed sympathy for those who have fallen ill, accused Trump of lacing his response with xenophobia, blasted him for disbanding the National Security Council’s global health team, and offered his own proposals to confront the virus.

“Unfortunately, this virus laid bare the severe shortcomings of the current administration," Biden said. “Public fears are being compounded by a pervasive lack of trust in this president.”

Trump’s campaign, in turn, called Biden “incompetent” and attacked him for comments he made as vice president during the 2009 swine flu outbreak.

“America needs leadership and Biden has shown none,” Trump spokesperson Tim Murtaugh said. Trump’s “every move has been aimed at keeping Americans safe,” Murtaugh said, "while Joe Biden has sought to capitalize politically and stoke citizens’ fears.”

Sen. Bernie Sanders, Biden’s fading Democratic primary opponent, delivered his own remarks a short time later in Burlington, Vt. Like Biden, he blasted Trump for dishonesty and downplaying science, and said the president’s “incompetence and recklessness” have endangered lives. Sanders ominously warned that the virus could kill more people than the U.S. armed forces lost in World War II.

He spent much of his address returning to his regular themes of economic inequality. He said the United States was “at a disadvantage” because it doesn’t guarantee health-care coverage, and he called for aid for working people, from a moratorium on evictions to expanded unemployment coverage for those who lose jobs and service workers who depend on tips.

“We cannot live in a nation where if you have the money, you get the treatment you need to survive, but if you’re working class or poor, you get to the end of the line,” Sanders said.

Biden has a notable history with crises, from both personal loss and as a key figure in President Barack Obama’s administration. Obama’s 2008 campaign was buffeted in its final weeks by the worst economic crash in a generation, and the financial wreckage was upon the administration as soon as it took office.

“When major crises hit during the course of a campaign it can completely change the focus,” said Ben LaBolt, a press aide on Obama’s campaign.

Obama’s calm, even demeanor became an asset as the country faced a panic.

“The tone and tenor was ‘This is a grave situation, we understand the urgency of it, we understand the pain people are feeling, and we are involved in an around-the-clock effort to address it,’ " LaBolt said.

Every president faces unexpected moments that test not their political strength, but competence, empathy, attention to detail, and command. Along with the economy, Obama had a rash of wrenching mass shootings. George W. Bush faced the Sept. 11, 2001, terrorist attacks and, later, Hurricane Katrina.

His response to the first burnished his national standing. The second depleted it.

“Natural disaster or crises are make-or-break moments for political leaders,” said Whit Ayres, a Republican pollster in Virginia. “A successful response consists of effective mitigation efforts, coupled with clear, transparent, and consistent communication.”

None of those, however, have been Trump hallmarks.

The president is most comfortable in combat and chaos, defying expectations and Twitter-blasting his enemies. He is usually uninterested in policy details or expert advice.

And he has at times appeared awkward, or callous, in moments of suffering, as when he tossed paper towels to stricken Puerto Ricans as if he were shooting baskets after a devastating hurricane.

Trump addressed the country Wednesday night in somber tones and with all the Oval Office trappings of a president trying to reassure the public. He spoke calmly, if stiffly, and on script.

“I will never hesitate to take any necessary steps to protect the lives, health, and safety of the American people,” Trump said. “The virus will not have a chance against us.”

Yet Trump and his aides almost immediately walked back or clarified several parts of his remarks. They clarified that a travel ban from Europe would not apply to U.S. citizens and permanent residents, nor to goods, contrary to Trump’s speech. The lobbying group for health insurers added that its members would waive co-payments for coronavirus testing, but not treatment, as Trump had also said.

And the speech came after weeks of downplaying the virus’ risks, spreading misinformation (such as claiming a vaccine could be ready soon), and treating the crisis as a political fight. At one point he described it as Democrats’ “new hoax."

The pandemic, however, may be impervious to Trump’s talent for bending narratives. The consequences are already playing out not just on cable news but in people’s lives: Events have been canceled, schools closed, and students rushed home from college. Sports and festivals are shutting down.

Biden, who as a challenger has the advantage of being able to propose a plan without executing it, called for free public testing; paid family and medical leave; better coordination with state, local, and foreign governments; and restoring the health team Trump eliminated.

Despite the peril of the moment, it also represents an opportunity for Trump to show his leadership, Ayres said. In 1989, Ayres was part of the administration of South Carolina Gov. Carroll Campbell when Hurricane Hugo struck. “His response to that disaster was so superb that he was basically untouchable for reelection in 1990,” Ayres said.

If, before long, the virus is contained and fears subside, the crisis may seem less significant than feared. Potentially, Trump could claim credit for guiding the country through a frightening time.

Biden and Sanders are betting that, instead, it will leave voters wanting new leadership.