WASHINGTON - Republican frontrunner Donald Trump and rival Ted Cruz both had victories Tuesday in the U.S. presidential race.  Trump easily won the Arizona primary while Cruz won a lopsided victory in caucus voting in Utah. 

The results did little to change the overall trajectory of the race, with Trump leading Cruz by a wide margin in the delegate count and on track to have nearly all the votes he needs to claim the Republican nomination by the time the party’s national convention opens in mid-July.

But even as Trump moves closer to securing the Republican Party nomination, many establishment Republicans remain hesitant to heed his call for party unity behind him as the expected nominee.

Trump told a Washington news conference Monday he believes he will win enough delegates to claim the nomination before the party convention in July, and he says it’s time for reluctant party leaders to unite behind him. 

“If people want to be smart, they should embrace this movement,” Trump said at the site of his new hotel in Washington, still under construction.  “If they don’t want to be smart, they should do what they are doing now and the Republicans are going to go down to a massive loss.”

Prospects of an open convention

But if Trump fails to secure enough delegates to nail down the nomination at the convention, a multi-ballot open convention could ensue, with an unpredictable outcome.

House Speaker Paul Ryan of Wisconsin talks to repo
FILE - House Speaker Paul Ryan of Wisconsin talks to reporters on Capitol Hill in Washington, March 3, 2016. Ryan has been mentioned as a possible compromise candidate if the Republican party has no clear nominee by its convention in mid-July.

House Speaker Paul Ryan, the convention chairman, has been mentioned by some as a possible compromise candidate if there is a deadlock. 

“This is more likely to become an open convention than we thought before,” Ryan told reporters at the Capitol recently, "so we are getting our minds around the idea that this could very well become a reality, and therefore those of us who are involved in the convention need to respect that.”

Some conservatives, led by rival Ted Cruz, continue to resist Trump’s rise toward the nomination, charging that the New York billionaire is not a true conservative. Cruz hopes to build momentum after getting the endorsement of former contender and Florida ex-governor Jeb Bush.

How likely is a contested Republican convention?

A conservative third-party bid?

Some are so disenchanted they are looking for a conservative to run as a third-party candidate in the general election, according to conservative columnist Fred Barnes. 

“I know many of them here in Washington who say they won’t vote for Trump, and then others who are starting to - and I think will succeed - in fielding a third party conservative Republican candidate against Trump,” Barnes said on VOA’s Issues in the News program.

Republican presidential candidate Sen. Ted Cruz, R
FILE - Republican presidential candidate Senator Ted Cruz speaks at a rally March 19, 2016, in Provo, Utah. Cruz continues to challenge Trump’s rise toward the nomination, charging that the billionaire is not a true conservative.

But many analysts believe that any attempt to deny Trump the nomination at the convention could tear the party apart. They include veteran political journalist Tom DeFrank of the National Journal

“How do you bring back the millions of disaffected Trump voters who are angry not only at President [Barack] Obama and [Democratic Party front-runner] Hillary Clinton, but who are also sick and tired of the Republican leadership in Washington.  How do you get them back in the tent (in the party’s mainstream)?”  said veteran political journalist Tom DeFrank of the National Journal, who also appeared on Issues in the News.

Foreign policy has once again taken center-stage in the campaign in the aftermath of the terror attacks in Brussels. 

Rivals question Trump's 'temperament'

Trump rivals Cruz and John Kasich both have vowed to fight Trump all the way to the convention. Both also question whether Trump has the right temperament to be commander in chief.

Cruz seized on a Trump interview with The Washington Post, in which he said it was time for the U.S. to scale back its financial commitment to NATO and to reassess its military deployments in Asia.

"The Obama-Clinton retreat from the world is very much the retreat from the world that Donald Trump is advocating,” Cruz told reporters in Washington. “Even Barack Obama hasn’t gone so far as to argue for withdrawing from NATO the way Donald Trump has.”

Republican U.S. presidential candidate John Kasich
FILE - Republican presidential candidate John Kasich addresses supporters in Grosse Pointe Woods, Michigan, March 7, 2016. Kasich continues to argue that his long experience in Congress and his tenure as Ohio governor make him the best alternative to Trump and Cruz.

Kasich continues to try to make the case that his long experience in Congress and his tenure as Ohio’s governor make him the best fit for establishment Republicans looking for an alternative to both Trump and Cruz.

Speaking to reporters in Minneapolis, he said of the party's mainstream members: "They really say, who can win in the fall and who has both the domestic and the foreign policy experience to run the country?”

Cruz and Kasich will have their next shot at Trump in the Wisconsin primary on April 5.