This is being hailed as one of the most surprising political recoveries in recent American history.
Joe Biden was widely seen as dead and buried after the nomination battles in Iowa and New Hampshire. He came a humiliating fourth and fifth place in those contests.
There was talk about the former Vice President having to drop out of the race. He had no money, no energy, no message.
But, wow, how that has changed overnight! Now Biden is seen as the clear favourite for the Democratic nomination.
He didn’t just do well last night in his strongholds in the South - Alabama, Tennessee, North Carolina - where African American voters are his core voters.
Biden also seized Massachusetts, the home state of Elizabeth Warren. He won Minnesota, widely seen as a progressive bastion that would favour Bernie Sanders.
And it looks almost certain that Biden will win the major prize of Texas, another huge upset.
So this amounts to a big setback for the campaign of his chief rival, the indefatigable Bernie Sanders. The Senator from Vermont had spoken of building a unique coalition consisting of young voters, Hispanics, and the white working class, that would propel him to the nomination.
It did win Sanders the state of California, but elsewhere that coalition has fractured. In the last 48 hours many Democrats decided to flee to the safety of Biden, judging him to be a stronger candidate to face Trump in November.
Biden also benefited from a sudden consolidation of the moderate candidates. Amy Klobuchar and Pete Buttigieg abandoned their campaigns and endorsed Biden.
That was calculation, not charity. They can have high expectations of key jobs in a Biden Administration.
The Establishment’s stop-Bernie-at-any-cost campaign was brutally effective.
But there are questions left swirling in the Democratic Party firmament this morning. Can the party unite its two fractious wings? Will radical activist who adore Sanders agree to support Biden?
And, of course, the biggest imponderable of all: How does Biden match up against Donald Trump? Can the former VP surprise everyone and win the White House?
We will know in 244 days.