CLEVELAND — John Kasich was locked in a close race with Donald Trump in the Ohio governor's home-state Republican primary Tuesday, a make-or-break contest for Kasich. In the night's other crucial GOP primary, Trump held an early lead in Florida, while Hillary Clinton had an advantage in Florida's Democratic race as the first votes were counted.
Polls had closed in Ohio and North Carolina, but the races in both parties were too close to call.
For both Republicans and Democrats, the five states voting Tuesday could bring clarity about Clinton and Trump's strength as front-runners. It could also dash the White House hopes of Kasich and Florida Sen. Marco Rubio if they're unable to win at home.
Even before Florida's results were final, Rubio's team was preemptively saying the candidate's struggle was due in part to an optimistic message that did not match the angry and fearful mood of the electorate.
Illinois and Missouri were also voting Tuesday.
For Democrats, the primaries offered front-runner Clinton a chance to solidify her lead over Bernie Sanders, while the Vermont senator was hoping to build on a surprising win last week in Michigan.
Reprising a theme that helped propel that victory, Sanders has pounded Clinton's past support for trade deals such as the North American Free Trade Agreement, which he says has been a job-killer in the U.S.
"When it came down whether you stand with corporate America, the people who wrote these agreements, or whether you stand with the working people of this country, I proudly stood with the workers," Sanders said during a campaign stop Tuesday in Ohio. "Secretary Clinton stood with the big money interests."
According to early exit polls, Democratic voters were more likely to describe Sanders as honest, but more likely to describe Clinton's policies as realistic.
Clinton's campaign was bracing for potentially close contests in the Midwest, but she was bullish about her prospects in Florida, the day's biggest prize.
Campaigning Tuesday in North Carolina, Clinton said "the numbers are adding up in my favor." She signaled an eagerness to move on to a possible general election showdown with Trump, saying he's laid out a "really dangerous path" for the country.
Trump entered Tuesday's primaries embroiled in one of the biggest controversies of his contentious campaign. The GOP front-runner has encouraged supporters to confront protesters at his events and is now facing accusations of encouraging violence after skirmishes at a rally last week in Chicago.
The vibe at Trump's events has deepened the concern over his candidacy in some Republican circles. Rubio and Kasich have suggested they might not be able to support Trump if he's the nominee, an extraordinary stance for intraparty rivals.
Trump's closest competition so far has come from Texas Sen. Ted Cruz, who is keeping close to the businessman in the delegate count. Cruz has been urging Rubio and Kasich to step aside and let him get into a one-on-one race.
Even before Tuesday's results, however, a group of conservatives was planning a meeting to discuss options for stopping Trump, including at a contested convention or by rallying around a third-party candidate. While such no candidate has been identified, the participants in Tuesday's meeting planned to discuss ballot access issues, including using an existing third party as a vehicle or securing signatures for an independent bid.
A person familiar with the planning confirmed the meeting on the condition of anonymity because they were not authorized to discuss the gathering by name.
If Trump sweeps Tuesday's contests, he'll cross an important threshold with more than 50 percent of the delegates awarded so far.
Despite concerns from party leaders, Republican voters continue to back Trump's most controversial proposals, with two-thirds of those who participated in GOP primaries Tuesday saying they support temporarily banning Muslims from the United States.
The exit polls were conducted by Edison Research for The Associated Press and television networks.
Trump won easily in the Northern Mariana caucus on Tuesday, picking up nine delegates. That gave him 469 to 370 for Texas Sen. Ted Cruz, 163 for Rubio and 63 for Kasich. It takes 1,237 to win the GOP nomination.
Entering Tuesday, Clinton had 768 pledged delegates compared to 554 for Sanders, according to an analysis by The Associated Press. Overall, Clinton holds 1,235 total delegates, more than half the number needed to clinch the nomination when the count includes superdelegates, who are elected officials and party leaders free to support the candidate of their choice. Sanders has 580 when the count includes superdelegates
Pace reported from Washington. AP writers Scott Bauer in Rockford, Illinois, Lisa Lerer in Chicago, Sergio Bustos in Miami, Stephen Ohlemacher and Alan Fram in Washington contributed to this report.