Donald Trump won a decisive victory in the Florida primary over Marco Rubio, who suspended his campaign after learning the results.

On the Democratic side, Clinton crushed rival Bernie Sanders in Florida and in North Carolina, which also held a primary. Her victories raised the possibility that she will only expand her wide delegate lead.

Florida, North Carolina, Ohio and two other states -- Illinois and Missouri -- went to the polls in what cable networks had dubbed "Super Tuesday III." It was shaping up to be a pivotal day as Trump and Clinton looked for enough decisive victories to make their paths to the nomination unstoppable.

"Word is that, despite a record amount spent on negative and phony ads, I had a massive victory in Florida. Numbers out soon!" Trump tweeted, even before the race was called.

Rubio was hoping that he could upset in his home state, where Trump had a significant lead in most polls. As the youngest candidate in the race, Rubio was once viewed as someone who could unite factions of the GOP, while he pitched his campaign as a forward-looking contrast to Jeb Bush and Hillary Clinton. In fact, many Democrats saw Rubio as Clinton's most formidable potential rival.

"While this may not have been the year for a hopeful and optimistic message about our future, I still remain hopeful and optimistic four our country," Rubio said in conceding.

He said that "America is in the middle of a real political storm, a tsunami, and we should have seen this coming."

With Kasich denying Trump a victory in Ohio, analysts say it raises the likelihood that no candidate would have a majority of delegates by the time of the Republican National Convention in July.

Such a prospect has not played out in either party since 1976, when President Gerald Ford was challenged by Ronald Reagan. But Ford won the nomination on the first ballot, in a race that didn't have the powder-keg of anger and grievance playing out this year.

The past few days have seen Trump criticized by rivals for stoking anger and even violence at his rallies, along with a battering of attack ads chiding him for his rhetoric and past statements on women and minorities.

But Trump has capitalized on the attention, calling in to cable news shows, earning headlines for offhand remarks at rallies and relentlessly posting on Twitter. On Tuesday, the New York Times reported that Trump's ability to command news cycles has delivered huge amounts of so-called "free media" -- about $2 billion worth, according to the analytics firm mediaQuant.

That media dominance has in turn produced a flurry of media commentary on the ethics of giving one candidate so much airtime and mention -- critical pieces that also again give Trump more airtime and mention.

According to data analytics firm Zignal Labs, in the past week, Trump has commanded 45% share of conversation on Twitter and 23% on broadcast TV.

That ability to hog airtime is likely to continue on Tuesday: Trump has scheduled an evening press conference.