Donald Trump has won Florida's primary election in a landslide, defeating Senator Marco Rubio in his home state, multiple news outlets called early Tuesday night.

Trump's win was expected: He's had a strong lead in the Florida polls for months, and it's only strengthened in recent weeks. He went into the election leading by nearly 20 points in Real Clear Politics' polling average.

But this blowout defeat makes clear just how badly Rubio — once considered the future of the Republican party — has struggled in the presidential race. And Rubio himself was banking on Florida as recently as a week ago.

Marco Rubio (March 8): "I believe with all my heart that the winner of the Florida primary...will be the nominee of the Republican Party." — Matt Viser (@mviser) March 15, 2016

Marco Rubio (March 6): "I have never based my campaign on one state but I can tell you this, we will win the state of Florida." — Matt Viser (@mviser) March 16, 2016

Because Florida, with Ohio, is one of the first winner-take-all states, where all the delegates go to the winner with none awarded to any other candidates, it's an important victory for Trump.

Marco Rubio's campaign is probably toast

Before it became clear that the Trump campaign was an electoral juggernaut, Florida should have been a hard-fought state. Former Governor Jeb Bush and Rubio were squaring off, a scion of an old American political family versus a young up-and-comer.

Suffice to say it didn't work out that way. Bush dropped out after a horrible showing in South Carolina, and after his campaign generally failed to catch on — he might be most memorable for serving as a punching bag for Trump.

After Bush dropped out, much of his Florida support shifted to Rubio. But Rubio kept touting a string of second- and third-place victories as unlikely comebacks until it became clear that the winnowing Republican field still wasn't going to deliver enough votes for him to score victories. And because Rubio decided to resign his Senate seat to focus on his presidential campaign, his future is uncertain.

Even before tonight's results, the autopsies for Rubio's campaign were already rolling in. In the New York Times, Mark Leibovich argued that Rubio was the wrong candidate for the moment:

Rubio is always saying that he represents "new leadership for the 21st century." This notion has proved almost entirely at odds with the views of the party’s aging, shrinking base. Trump’s message has been neither forward-looking nor optimistic. The front-runner’s America is essentially a weak and scary place, in need of being made great again.

Buzzfeed's McKay Coppins pointed to something more concrete. Rubio wasn't campaigning on the ground, but relied on a strategy of interviews on TV and with conservative talk radio. And that strategy failed as soon as Trump became a serious candidate whose every utterance was given wall-to-wall media coverage:

The more costly long-term consequence of the Rubio campaign’s strategic reliance on national media may end up being how it de-prioritized building an effective ground game outside the early states. While Rubio prevailed over Ted Cruz in South Carolina and Nevada, the Texan’s campaign has since consistently out-hustled his rival in getting voters to the polls — especially in caucuses, where grassroots organization is crucial.

The only argument now for Rubio's campaign is that he could continue to draw votes away from Trump and make a contested convention more likely by denying the frontrunner an outright majority. That probably isn't good enough for donors, and the calls for Rubio to drop out, already echoing before the Florida primary, are about to get a lot louder now that he's lost big in his home state.

It's not yet clear if Trump will have a good night or a very good night. But either way, his delegate haul in Florida is his biggest yet, and it could set him up for a clearer path to the nomination.