- Republicans vote in Arizona and caucus in Utah; Democrats also caucus in Idaho
- Ted Cruz hopes to win the 50% needed to capture all of Utah's delegates
For Republicans, the stakes may be highest for Ted Cruz and his quest to keep a path alive to winning the nomination outright. As the race goes on, Cruz and particularly Ohio Gov. John Kasich's chances of stopping Trump are increasingly dependent on keeping him from reaching the 1,237 delegates necessary to capture the GOP nomination outright, forcing the contest to play out at the Republican National Convention in Cleveland in July.
With the lead in the delegate race, Trump also is favored nationally among Republicans, with a CNN/ORC poll out Monday night showing that 47% of Republicans nationally support Trump, compared to 31% for Cruz and 17% for Kasich.
Here are 5 things to watch:
Will Cruz reach his magic number in Utah?
In Utah, Cruz is hoping to reach a magic number: 50%. If he gets the support of more than half the state's Republicans, he won't just run up a delegate advantage -- he'll capture all 40 on the line there.
It's a critical hedge against Arizona, a state where the winner takes all 58 delegates -- no matter the final percentages -- and where polls have shown Trump running stronger.
Cruz has pulled out all of the stops in the Beehive State, including Mitt Romney, the 2012 GOP presidential nominee who is a Mormon and votes in Utah said he'll be caucusing for Cruz there. And he recorded robocalls on Cruz's behalf that are reaching voters in Utah and Arizona.
Can Kasich maintain the rationale for his candidacy?
Utah Gov. Gary Herbert also endorsed Cruz on Monday, noting that he's most likely to reach 50% and defeat Trump in the state -- a decision that was surprising, since Herbert had appeared at a Kasich campaign event on Friday. Romney also previously appeared at a Kasich rally, but emphasized that any help for Kasich was in reality a boost for Trump.
Kasich is in the midst of a challenging stretch of the campaign. Polls have not shown him within striking distance in either of the states voting Tuesday, and his next chance at a win comes two weeks from Tuesday, on April 5 in Wisconsin.
That reality put Kasich in Cruz's crosshairs in an interview on Fox News on Monday night.
"If John Kasich were not in the race, we would get to 1,237" delegates, Cruz said. He added that Kasich is a "spoiler if he pulls just enough votes to let Trump win states."
Kasich, for his part, said he's looking ahead to taking his case to the convention in his home state of Ohio. The governor added on CNN's "Final Five" program that he won't take a deal with Trump or Cruz that puts him on the ticket as a vice presidential nominee.
Can Trump advance his path to 1,237 delegates?
Trump spent Monday in Washington on a goodwill tour of sorts. He met with lawmakers and some GOP establishment types just off Capitol Hill, sat with The Washington Post editorial board and gave a speech at the American Israel Public Affairs Committee conference, touting his pro-Israel credentials and opposition to the Iran nuclear deal.
But foremost is still the mater of winning the 1,237 delegates. In an interview with Wolf Blitzer as part of CNN's "Final Five" program, Trump warned the party against blocking him from the nomination if he falls just short of the magic number.
"If it was at 1,190, so I am a little bit off .... I think it is going to be very hard for them to do," Trump said, later adding that it was "a little unfair" that he had been forced to compete against an unusually large field of contenders.
"I had many, many people that I am competing with, so you know when you talk about the majority plus one it is a very unfair situation," Trump said.
Can Sanders get his momentum back?
Hillary Clinton will try to turn her advantage among minority voters into another win in Arizona -- while Bernie Sanders looks to best Clinton in caucuses in Utah and Idaho.
The contests are important tests for Sanders, who one week earlier lost five big-state contests to Clinton and has long argued he can run up delegate advantages when the campaign moved West.
He's under increasing pressure from Democrats to drop his attacks on Clinton -- even if he doesn't get out of the race -- to avoid hampering her prospects in the general election.
To keep Clinton from getting that far, he'll need to close a widening delegate gap in rapid fashion.
And he's arguing that Republican-leaning Western states are the place to do it.
"I think it would be just extraordinary for this country if what is perceived to be a conservative state like Idaho stood up and said, 'We are part of the political revolution,'" Sanders said Monday in Boise, Idaho.
Can Clinton win big enough to keep her focus on Trump?
Clinton, meanwhile, is aiming to rack up a higher delegate count than Sanders on the night -- with Arizona's 75 on the line carrying the potential to offset Sanders' possible gains with Utah's 33 delegates and Idaho's 23.
If she can keep Sanders from catching up, she can keep her focus on attacking Trump -- instead of the Democratic contest.
It's more than an effort to get a head start on defining a general-election foe. Clinton faces a serious challenge in -- if she wins the party's nomination -- turning Sanders' loyal, energetic supporters into backers of her campaign. The harder she hits Sanders, the tougher that job becomes.
If the two don't have much in common, at least they share an enemy. And as Trump grows more controversial -- with liberals increasingly engaging in mass protests and efforts to shut down his events -- taking on Trump could be the best opportunity Clinton has to win over reticent Democrats.
Clinton blasted Trump in CNN's "Final Five" forum Monday night.
"He has been engaging in bigotry and bluster and bullying and I think when it comes to understanding what he would do as president, there are serious questions that have been raised, and this campaign should he be the nominee will have to address them," Clinton said.
The former secretary of state accused Trump of inciting violence and urging supporters to go after protesters in a way that she said "raises very serious questions."
Asked whether Trump would behave differently as president, Clinton answered, "Who knows?"