Washington: Republican Donald Trump and Democrat Hillary Clinton could emerge from Tuesday's primary elections in five states as presumptive presidential nominees, setting up a head-to-head race amid concerns about violence and campaign rhetoric that President Barack Obama called "vulgar and divisive."
Without mentioning Trump by name, Obama drew a standing ovation with his comments at a lunch at the Capitol attended by leaders from both major political parties.
The billionaire real estate baron has urged supporters to physically confront protesters at his campaign events and now faces criticism for encouraging violence after skirmishes broke out at a rally last week in Chicago.
Trump, who has denied playing any role in encouraging violence against protesters, appeared defiant. "I don't think I should be toning it down because I've had the biggest rallies of anybody probably ever," he told ABC before Obama's remarks." ''We have had very, very little difficultly."
Florida and Ohio were the biggest prizes Tuesday, but Missouri, Illinois and North Carolina also were awarding a large cache of delegates to the parties' national nominating conventions.
While Trump could take all five states, that still would not assure he goes into the Republican convention this summer with the needed majority of delegates. His closest competition has come from Texas Sen. Ted Cruz, who has won in seven states. Trump also must overcome Florida Sen. Marco Rubio and Ohio Gov. John Kasich, who are battling for their political life in their home states Tuesday.
Clinton, once seen as the clear favorite for the Democratic nomination, still faces a challenge from Vermont Sen. Bernie Sanders, who has shown surprising staying power after pulling off an upset victory in the industrial state of Michigan and is trying to build momentum in the Midwest.
If Clinton comes out of Tuesday's contests with decisive wins in several states, it would be difficult for Sanders to catch her because all the state Democratic nominating contests allot their delegates proportionally. Tuesday's voting has 691 delegates at stake for the Democrats.
Trump holds a comfortable lead in the Republican delegate count. If he sweeps Tuesday's contests, he would cross an important threshold by collecting more than 50 percent of the delegates awarded so far.
While polls show Trump leading Rubio in Florida's winner-take-all contest for 99 delegates, Kasich holds a narrow lead in Ohio, where 66 delegates are at stake.
That makes Ohio the key state in determining whether Trump puts himself on a path to winning the nomination by the end of the primary season on July 7. A loss there means the race could result in a contested convention.
The violent atmosphere at some Trump events has deepened 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.
Kasich, who has been restrained in his criticism, said Tuesday he would be "forced, going forward, to talk about some of the deep concerns" he has about Trump's campaign.
Trump won easily in the Northern Mariana territorial caucus on Tuesday, picking up nine delegates. That gave him 469 to 370 for Cruz, 163 for Rubio and 63 for Kasich. It takes 1,237 to win the Republican nomination.
Clinton headed into Tuesday's primary with 768 pledged delegates compared to 554 for Sanders, according to a count by The Associated Press. Including superdelegates, elected officials and party insiders who are free to choose any candidate, Clinton has 1,235 total delegates, more than half the amount needed to clinch the nomination, while Sanders has 580.
For the Democrats, 2,383 delegates are needed to win the nomination.