First Read: A scary time in American politics

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.

A scary time in American politics

We love American politics because of its excitement, its unpredictability, and its clash of ideas and policies. But we've never seen this in our lifetimes until now -- when politics becomes scary. And that has been the overarching political story over the past 96 hours, as Donald Trump rallies have featured sucker punches, scuffles, unrest, and even a protester trying to jump on the stage. We're all on edge that something even scarier might happen, which is something Trump supporter Ben Carson suggested on "Today" this morning. "I think certainly if the protesters continue with their Alinksy-ite tactics, there is a real possibility of escalation because those who are the victims of them have two choices: They can submit to them and meekly just do whatever those protesters want them to do, or they can fight back. And if they decide to fight back there could be an escalation." And as we said on Friday, it's on the candidate for setting the tone at his/her rallies. But on "Meet the Press" yesterday, Trump said he wasn't responsible for the unrest. "I don't accept responsibility; I do not condone violence in any shape." And he mentioned that he's "instructed" his people to look into covering the legal fees for the man who sucker punched the protester.

Where is the rest of the GOP establishment?

Yesterday, NBC's Hallie Jackson reported that Mitt Romney will campaign today for John Kasich during two stops in Ohio -- all in an effort to stop Trump. (Jackson reports that the campaigning isn't an endorsement.) But we have to ask: Where is the rest of the Republican Party? The Bushes? The Cheneys? Paul Ryan? Condi Rice? After the last 96 hours in politics, their silence is pretty stunning.

NBC/WSJ/Marist polls: Trump ahead in Florida, Illinois; Kasich leads in Ohio

Tuesday brings us GOP and Democratic primaries in Florida, Illinois, Missouri, North Carolina, and Ohio -- with Florida and Ohio being winner-take-all states on the Republican side. And we're dubbing tomorrow Separation Tuesday, because we're either going to see Trump and Clinton further separate themselves from their competition, or we won't. On Sunday, we released three new NBC/WSJ/Marist polls:

• In Florida, Trump holds a 2-to-1 advantage among likely GOP voters over Marco Rubio, the state's U.S. senator, 43%-22%. They're followed by Ted Cruz at 21% and John Kasich at 9%.
• In Illinois, Trump gets the support of 34% of likely GOP primary voters, Cruz gets 25%, Kasich gets 21% and Rubio gets 16%.
• But in Ohio, Kasich, the state's incumbent governor, holds a six-point lead over Trump, 39% to 33% - followed by Cruz at 19% and Rubio at 6%.

And this morning, Quinnipiac has new Republican numbers for Florida (Trump 46%, Rubio 22%, Cruz 14%, Kasich 10%) and Ohio (Trump 38%, Kasich 38%, Cruz 16%, Rubio 3%).

Why Clinton winning three of five Separation Tuesday states would be a good night for her -- and why losing three would be another rough night

Meanwhile, our NBC/WSJ/Marist polls show Hillary Clinton leading all three states:

• In Florida, Clinton is ahead of Sanders among likely primary voters by 27 points in Florida, 61 percent to 34 percent;
• In Ohio, she's up by 20 points, 58 percent to 38 percent;
• But in Illinois, her lead is just six points, 51 percent to 45 percent.

The Clinton camp insists that the polling in Ohio is closer, and Quinnipiac finds her up by five points in the Buckeye State, 51%-46%, while it has her leading Sanders 60%-34% in Florida. And the Clinton campaign is insisting that it will still best Sanders in delegates -- no matter what happens in Ohio, Illinois, or Missouri. "Even if he won in Ohio [and] Illinois," Clinton campaign manager Robby Mook told the New York Times, "we would still have more delegates on the 15th because of their performance in delegate-rich Florida and North Carolina." That's true. But Clinton winning three out of the five states on Tuesday -- say Florida, North Carolina, and Ohio -- would be a good night for the campaign. But losing three out of five -- with the polling lead in Ohio -- would produce another round of negative news cycles like we saw after Michigan. Starting at 6:00 pm ET, MSNBC features back-to-back Sanders/Clinton town halls.

Doing the delegate math: Why Florida and Ohio are so important for Trump

Below is our latest math after GOP delegates were awarded from DC and Wyoming over the weekend, and here is the stark reality: Trump really needs to win both Florida and Ohio to be on a path to winning 1,237 delegates. And after the past weekend, you could argue that he has no margin for error -- if he's short, you could see a real effort to deny him the nomination in Cleveland.

Trump currently holds an 84-delegate lead over Ted Cruz

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Trump must win 53% of all remaining delegates to reach 1,237 magic number

Cruz must win 80% of all remaining delegates to reach 1,237 magic number

Trump must win 60% of all remaining delegates to reach 1,237 magic number

Cruz must win 80% of all remaining delegates to reach 1,237 magic number

Kasich must win 110% of all remaining delegates to reach 1,237 magic number

Trump must win 70% of all remaining delegates to reach 1,237 magic number

Cruz must win 80% of all remaining delegates to reach 1,237 magic number

Rubio must win 95% of all remaining delegates to reach 1,237 magic number

Kasich must win 110% of all remaining delegates to reach 1,237 magic number