Winning there is necessary to keeping his candidacy alive. Mr. Rubio and Mr. Kasich's home states of Florida and OH vote on March 15.
Texas Senator Ted Cruz walked away with three states, bringing his total to four, while Florida Senator Marco Rubio won his first state (Minnesota) in the primary race to date.
"He would be a disaster for America".
A Republican senator who asked not to be identified, and a senior aide to another Republican senator, told Reuters that many private conversations were underway on Capitol Hill about finding ways to slow or stop Trump.
Super Tuesday - with voters in 12 states heading to the polls or caucus sites - could make the Republican presidential nomination largely inevitable for Donald Trump, political experts say. "Beyond Florida, I'm going to campaign as long as it takes to ensure that our party does not fall into the control of a con artist".
Yet the declarations and the panic mood by some in the GOP of "he can't be, he won't be" belies the fact that, in the more important component of the presidential nomination battle, Trump is at the same delegate count, post-Super Tuesday, that Mitt Romney was in 2012. And I don't think Donald Trump, who mocked Rubio as a "lightweight" at his victory news conference, is exactly quaking in his boots. None of them has a clear path to hitting that threshold on their own, as the race shifts to provoking a contested convention to block the bombastic delegate leader. Cruz is in second place with 226, and Rubio has 106.
But it was Cruz who used his wins in Texas and Oklahoma to frame the contest as a two-man race, calling for the other candidates to drop out. Marco Rubio (R-FL) and Sen.
Senator Ted Cruz reasserted himself with victories in his home state, Texas, in neighboring Oklahoma and in Alaska, earning a reprieve as he fends off questions about his viability.
"The stakes have never been higher".
This won't help Republicans much, since all their other candidates appear to be getting unpopular even faster than Trump.
You know it's been a rough day for a political party when its two top leaders feel compelled to denounce racism within the ranks - as House Speaker Paul Ryan and Senate Majority Leader Mitch McConnell did Tuesday.
Still, Brown, who endorsed Trump before the New Hampshire primary, was quick to note that he and the Donald don't see eye-to-eye on everything.
What's more, the Vermonter continues to struggle badly to win African-American voters, and in the modern Democratic Party, that's a recipe for failure on a national level.
Trump won at least 234 delegates on Tuesday, and Cruz won at least 209.
Rubio tried to get into the gutter with Trump last week, insulting Trump on everything from his spray tan to his anatomy, and it didn't work.
There were still 33 delegates left to be allocated on Wednesday.
Maybe retired neurosurgeon Ben Carson will listen, though he too vowed to keep going. Securing the nomination requires 1,237 delegates.