HARI SREENIVASAN: The presidential hopefuls are pointing to a new round of voting tomorrow, with the leaders hoping to pad their leads, and rivals hoping to close the gap.
With that in mind, all of the candidates were on the road today.
DONALD TRUMP (R), Republican Presidential Candidate: Who is going to win North Carolina?
DONALD TRUMP: Right?
HARI SREENIVASAN: Donald Trump spent his day down South, where he's won eight states and the bulk of his 384 delegates so far.
DONALD TRUMP: Uh-oh. We have another one. Get him out of here.
HARI SREENIVASAN: Along with big crowds, the Republican front-runner again faced protesters.
DONALD TRUMP: Go home to mommy. Tell her to tuck you in bed.
HARI SREENIVASAN: And he still has to contend with Ted Cruz as well. The Texas senator is now within 100 delegates of Trump, after scoring weekend wins in Kansas and in Maine.
SEN. TED CRUZ (R-TX), Republican Presidential Candidate: In this race, it is clear. A vote for any other candidate, a vote for Marco Rubio or a vote for John Kasich is a vote for Donald Trump, because there is only one who has repeatedly beaten Donald Trump.
HARI SREENIVASAN: Marco Rubio managed to win Puerto Rico yesterday, but his real hopes now rest on his home state of Florida next week.
SEN. MARCO RUBIO (R-FL), Republican Presidential Candidate: We knew this would be the roughest period in the campaign, given the makeup of the electoral map.
FORMER GOV. ARNOLD SCHWARZENEGGER (R), California: Welcome my very good friend Governor John Kasich!
HARI SREENIVASAN: Ditto John Kasich, the Ohio governor who hopes to fare better in neighboring Michigan, one of four states holding Republican contests tomorrow.
Meanwhile, Democrats Hillary Clinton and Bernie Sanders held their testiest debate yet last night. They faced off in Flint, Michigan, the town where lead poisoned the drinking water, and both of them laid into Republican Governor Rick Snyder.
SEN. BERNIE SANDERS (VT-I), Democratic Presidential Candidate: He should resign.
HILLARY CLINTON (D), Democratic Presidential Candidate: I agree. The governor should resign or be recalled.
HARI SREENIVASAN: After that, the pair agreed on little else. Sanders hit Clinton on trade.
SEN. BERNIE SANDERS: Secretary Clinton supported virtually every one of these disastrous trade agreements written by corporate America.
HARI SREENIVASAN: In turn, Clinton played up her support for President Obama's auto rescue plan.
HILLARY CLINTON: Well, I will tell you something else that Senator Sanders was against. He was against the auto bailout. I voted to save the auto industry.
HILLARY CLINTON: He voted against the money that ended up saving the auto industry. I think that is a pretty big difference.
SEN. BERNIE SANDERS: Whoa. Well, I — if you are talking about the Wall Street bailout, where some of your friends destroyed this economy…
HILLARY CLINTON: You know…
SEN. BERNIE SANDERS: … through — excuse me, I'm talking.
ANDERSON COOPER, CNN Anchor: Let him respond.
HILLARY CLINTON: If you're going to talk, tell the whole story, Senator Sanders.
SEN. BERNIE SANDERS: Let me tell my story. You tell yours.
HILLARY CLINTON: I will.
HARI SREENIVASAN: The two also sparred on gun control and Wall Street. Today, Sanders charged Clinton misstated his position on the auto bailout.
SEN. BERNIE SANDERS: I voted for that bailout and support of the workers in the automobile industry.
HARI SREENIVASAN: Clinton also stayed in Michigan, appearing to strike a conciliatory stance in Grand Rapids.
HILLARY CLINTON: I would hope to be able to enlist Bernie in helping me to reach out to his supporters if I am so fortunate enough to be the nominee.
HARI SREENIVASAN: Clinton won one state to Sanders' three over the weekend, but she's still well ahead in delegates, with 1,130, nearly half of what's needed. Democrats hold contests tomorrow in Michigan and Mississippi.
And late today, former New York City Mayor Michael Bloomberg said he will not run for president after all. He told The New York Times that he fears a three-way race would guarantee Donald Trump's election.