First Read is a morning briefing from Meet the Press and the NBC Political Unit on the day's most important political stories and why they matter.
The 2016 primary season heads to the West
The biggest story in America and the world is the overseas terrorist attack that rocked Brussels, which certainly will have political aftershocks at home and on the 2016 campaign trail.
But we begin with today's presidential nominating contests. A total of three western states hold races today -- three on the Democratic side (Arizona primary, Idaho caucuses, Utah caucuses), and two on the Republican side (Arizona primary, Utah caucuses).
While the public polling has been sparse, Hillary Clinton and Donald Trump are favored in Arizona, while Bernie Sanders has the advantage in Idaho and Utah, and Ted Cruz is the favorite in the GOP contest in Utah. Three important points to make about tonight: One, on the Republican side, Arizona is winner take all (58 delegates), and Utah is proportional (40 delegates) but winner take all if someone wins by more than 50%. Two, the Democratic contests in Arizona (75 delegates up for grabs), Idaho (23), and Utah (33) are proportional as always. And three, much of Arizona has ALREADY voted before today due to the early voting. "Of the 1.2 million eligible Maricopa County voters, about 894,000 requested early ballots for the presidential preference election, as the primary is officially known. So far, 54 percent or 464,067 have returned their ballots, according to Maricopa County Recorder Helen Purcell," the Arizona Republic says. "Pima County, the state's second-most-populated county, reported it mailed 224,083 ballots to voters and as of Friday, 61 percent, or 136,946, had been returned."
Tonight's final poll closing/door closing times
- 9:00 pm ET: Idaho
- 10:00 pm ET: Arizona
- 10:30 pm ET: Utah (D)
- 1:00 am ET: Utah (R)
At least 26 killed in terrorist attacks in Brussels
As for today's top news, "At least  people were killed Tuesday after explosions rocked the check-in zone of Brussels Airport and in the Belgian capital's subway. Officials raised the terror threat level, shut down all public transport in the city and advised locals to stay indoors after what appeared to be coordinated attacks," NBC News reports. "Belgium's federal prosecutor said one of at least two explosions at the airport was likely caused by a suicide bomber. Belgian Prime Minister Charles Michel added that it was 'dark moment for our country.'"
Donald Trump has already reacted to the attacks, tweeting, per NBC's Peter Alexander: "Do you all remember how beautiful and safe a place Brussels wss. Not anymore, it is from a different world! U.S. must be vigilant and smart!" Trump also spoke to "Today" this morning, saying: "I'd be very, very tough on the borders… I would exclude the people from Syria who do not have documentation." And he spoke to Fox News: "I'd close up our borders to people until we figure out what is going on."
The GOP delegate race
Turning back to the presidential race at home, here are NBC's latest numbers going into today's Republican contests in Arizona (primary) and Utah (caucuses):
Trump holds a 258-delegate lead over Cruz
- Trump 685 (47% of delegates won)
- Cruz 427 (29%)
- Rubio 172 (12%)
- Kasich 143 (10%)
Trump needs to win 55% of remaining delegates needed to reach 1237 magic number.
Cruz needs to win 80% of remaining delegates needed to reach 1237 magic number.
Kasich needs to win 108% of remaining delegates needed to reach 1237 magic number.
The Democratic delegate race
And here are NBC's latest numbers going into Tuesday's Dem contests in Arizona (primary), Idaho (caucuses), and Utah (caucuses):
In pledged delegates, Clinton holds a 302-delegate lead over Sanders
- Clinton 1147 (58%)
- Sanders 845 (42%)
In overall delegates, Clinton holds a 720-delegate lead over Sanders
- Clinton 1583 (65%)
- Sanders 868 (35%)
Clinton needs to win 35% of remaining delegates to hit 2383 magic number
Sanders needs to win 65% of remaining delegates to hit 2383 magic number
Trump, Clinton maintain leads in NBC|SurveyMonkey tracking poll
And here are the results from the weekly NBC|SurveyMonkey online tracking poll:
GOP race: Trump 45% (+1), Cruz 24% (even), Kasich 16% (+4). "In this week's poll, Trump leads Cruz among overall white evangelicals by 7 points — 41 percent to 34 percent. This number, however, masks the fact that there are big differences among evangelical voters. If we divided white evangelicals into two groups — those who attend church more than once a week and those who do not — we find that Cruz is the favorite over Trump by a 15-point margin among those who attend church the most."
Dem race: Clinton 53% (-1), Sanders 41% (even)." Though Clinton did not see a rise in those committed to voting for her, nearly eight in 10 Democrats and Democratic-leaning voters now think she will win the Democratic nomination for president, which represents a 61 point margin over Sanders. This is a 7-point increase from the previous week before her string of victories on March 15."
On the trail
Hillary Clinton campaigns in Washington state, while Bernie Sanders hits California.