WASHINGTON — Bernie Sanders says the coronavirus pandemic highlights the need for the populist progressive political revolution he's been promoting for five years. Democrats aren't buying it.

The vast majority of them trust front-runner Joe Biden to handle a crisis more than they trust Sanders, according to NBC News polls in a series of states that held presidential primaries Tuesday. In Florida, 71 percent of voters picked Biden on that question, while 64 percent did in Illinois and 63 percent did in Arizona.

Biden's big wins in all three states meant he ended the night having expanded his controlling delegate lead.

The question now for progressives is whether it's their message or their messenger, Sanders, that Democrats are rejecting as the centrist Biden moves ever closer to winning the party's nomination and President Donald Trump pushes a coronavirus stimulus package that features a populist plan to send thousand-dollar checks to Americans.

"If we need an avatar for the progressive movement in this crisis moment, it should be Elizabeth Warren, and Bernie Sanders is not the ideal pick right now," Adam Green, co-founder of the Progressive Change Campaign Committee, said of the senator from Massachusetts who dropped out of the presidential campaign nearly two weeks ago. "She's a one-person think tank pumping out ideas hourly."

Sanders' continued presence in the race "incentivizes Biden to work with progressives" and is "a source of leverage," Green said. But he said Warren, who has proposed a $750 billion stimulus and a variety of specific policy ideas within that framework, demonstrated her own influence recently when Biden adopted her bankruptcy plan.

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With so much at stake, many progressives were disappointed that Sanders didn't present a stronger case against Biden during a debate Sunday in Washington, D.C. Congress, the White House and the Federal Reserve are pumping trillions of dollars into stimulating and stabilizing the economy. On the political left, there is concern that the flow of money could exacerbate systemic inequalities and hope that it could reduce them.

But as the polling and voting Tuesday demonstrated, Sanders' arguments didn't take hold with most Democratic primary voters — a set that is typically more progressive than the group of Democrats who show up to vote in general elections.

Sanders said the vulnerabilities revealed by the coronavirus crisis exist for the poor and the working class all the time and should be addressed permanently, not just on an emergency basis.

"Last year, at least 30,000 people died in America because they didn't get health care when they should, because we don't have universal coverage," he said. "I think that's a crisis. One out of 5 people in America cannot afford the prescription drugs they need. They suffer. Some die. I consider that a crisis. Bottom line is we need a simple system ... and that is if you are an American, you get the health care you need, end of discussion."

Biden dismissed Sanders as a broken record in pushing a single-payer universal health care insurance plan called "Medicare for All."

"Look, this is a national crisis — I don't want to get this into a back and forth in terms of our politics here," Biden said. "This idea that this is his only answer is a mistaken notion, but regardless of whether my plan was in place or his, this is a crisis. ... This is like a war, and in a war you do whatever is needed to be done to take care of your people. ... It has nothing to do with Bernie's Medicare for All."

Sanders was ineffective enough that he came back for a second pass Tuesday in a livestreamed speech on his website as election returns were being tabulated.

He called for Medicare to pay all medical bills during the crisis — regardless of whether they were related to the virus — emergency payments of $2,000 per month for every household, a moratorium on evictions and foreclosures, unemployment compensation of a full salary of up to $75,000 for anyone who loses a job and a variety of other measures.

He urged Americans not to turn to "fear and panic" but to remember people who are hurting during the crisis.

Sanders chose not to deliver public remarks on the results of Tuesday's primaries as Biden extended his lead in the race for pledged delegates to the Democratic National Convention. Calls for Sanders to exit the race are sure to continue to get louder from some corners of the Democratic Party.

But it may be that the best way to end his campaign without damaging Biden is a slow and quiet march toward non-competitiveness. If Sanders' most ardent supporters come to realize that he just can't beat Biden, perhaps they won't angrily reject the Democratic nominee come November.

The question would remain for progressives: Is Sanders the best voice for their movement?