At a Wednesday town hall, the senator said he hypothetically wouldn't agree to the second-highest position in the U.S.
The Miami contest comes ahead of the crucial March 15 Florida primary.
The two Democrats will face off in a debate, and Marco Rubio will participate in a one-man town hall.
It should not be assumed that denying Trump a first-ballot nomination means completely denying him the nomination.
Trying to be the candidate that taps into a shaken faith in American exceptionalism is a tricky task.
As Republican presidential candidate Donald Trump continues to rack up delegates in primaries and caucuses, talk has begun of a brokered Republican National Convention.
Trump is still crushing the establishment—just like McGovern and Goldwater before him.
On Thursday night, Donald Trump, Ted Cruz, Marco Rubio and John Kasich met in Detroit for the first Republican debate post-Super Tuesday. Here are the best moments from the 11th Republican presidential primary debate.
The candidates met Thursday in Detroit, which is 70 miles from the ongoing water crisis in Flint, Michigan.
The forum is the first since Donald Trump scored multi-state wins on Super Tuesday.
Dole wrote us an angry letter in 1990. Twenty-five years later, we asked him about it.
March marks the second month in the presidential election's primary season.
Several candidates' home states, including Vermont and Texas, are voting in Super Tuesday.
With dueling appearances in Arkansas and Georgia, the billionaire businessman and U.S. senator from Florida continued an onslaught of personal insults.
Former solicitor general Ted Olson lost his wife in the 9/11 attacks but is fighting for privacy over national security concerns.
An insane debate fades into an insaner day as the New Jersey governor backs Trump.
Finally, Rubio and Cruz turned their fire on Trump. But isn't it far too late?
At the debate on Thursday night, Trump said he is the only candidate who has hired people.