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.

Rubio seizes the moment. But is it too late?

You have to hand it to Marco Rubio: With the pressure on, he did everything right at last night’s debate. Rubio was aggressive from the get-go. He never let up (unlike previous attempts at going after the frontrunner). He got under Donald Trump’s skin by mocking him (a la Obama at the 2011 White House Correspondent’s Dinner). And he (often) prevented Ted Cruz from sharing the spotlight with him. Rubio, in fact, kept up the attacks on Trump this morning, telling NBC’s Matt Lauer: “We are not going to turn over the conservative movement to a con artist.” (That’s a strong attack, so strong that it’s hard to imagine Rubio ever endorsing someone after saying something like that.) And Rubio’s Super PAC is now slamming Trump in two new TV ads. (“Donald Trump put himself first, and us last,” goes one ad. “In today’s world, we can’t have a president who knows nothing about foreign policy,” goes the other.) “The only question we have is: Is it too late, especially with every Super Tuesday poll showing Trump with big leads outside of Cruz’s Texas, and with Trump leading Rubio in his home state? Ask yourself: Who would you rather be -- the GOP candidate who stood out at last night’s debate? Or the candidate who’s won three-straight contests and is leading in Florida in every single poll that’s been taken?

If Trump survives last night, he could look bulletproof after Super Tuesday

How Trump responds to Rubio -- the real-estate mogul today holds rallies in Texas and Oklahoma (the same places where Rubio will be today) -- will be telling. Remember, every time that Trump has sustained an attack on a rival, it has stuck: Jeb is low energy! Ben Carson made up his redemption story! Ted Cruz is a liar and a cheater! And last night, we got a preview of how Trump will probably react to Rubio: He’s a choke artist! He’s sweaty! He’s your average politician that’s bought and paid for by special interests! And Trump this morning tweeted, “Lightweight Marco Rubio was working hard last night. The problem is, he is a choker, and once a choker, always a choker. Mr. Meltdown.” But more than that, if Trump survives this thing -- after admitting he’s being audited by the IRS, after praising Planned Parenthood (again), after being mocked -- he’s going to seem bulletproof. How Super Tuesday plays out will be fascinating.

Did anyone look presidential last night?

We have a final observation about last night: Did anyone, in the end, look presidential? As we said earlier, Rubio shined and did everything that was asked of him. Ted Cruz landed some jabs on Trump. And guess what -- after an hour in, last night’s event looked more like a dumpster fire than a debate. If you want bring down Trump, you have to go down to his level. But there’s a price to pay for that.

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Only two possible delegate outcomes: 1) Trump as nominee or 2) a contested convention

That’s our conclusion after doing some back-of-envelope math looking ahead to Super Tuesday and the winner-take-all March 15 contests.

Trump currently has a 64-delegate lead over his nearest competition: Trump 81, Cruz 17, Rubio 17, Kasich 8, Carson 5

Trump could emerge with 100-plus delegate lead after Super Tuesday: Trump 289, Rubio 184, Cruz 154, Kasich 53, Carson 41 (assuming a Trump 35%, Rubio 28%, Cruz 23%, Kasich 8%, Carson 6% proportional split of delegates)

If Trump win Florida and Ohio, he’s more than halfway to nomination: And if Trump wins the winner-take-all states of Florida and Ohio on March 15, he’s at 650 delegates -- more than half of the 1,237 needed to win the GOP nomination (That assumes Trump wins 35% of the delegates up for grabs in the March 5-12 contests, as well as 35% of the proportional states on March 15.) Trump 650, Rubio 340, Cruz 278.

If Rubio wins Florida and Ohio, he’ll have a small lead over Trump: But if Rubio wins winner-take-all Florida AND Ohio, Rubio emerges with a *slight* overall delegate lead: Rubio 505, Trump 485, Cruz 278.

If Kasich wins Ohio, Trump will have slight lead: But if Kasich wins Ohio and Rubio wins Florida, it’s Trump 485, Rubio 439, Cruz 278, Kasich 148

The Super Tuesday strategies

With the Dems’ South Carolina contest tomorrow and with Super Tuesday in four days, here is everyone’s Super Tuesday strategies:

Clinton: GA, SC (Friday); AL, SC (Saturday); AR, TN (Sunday); TN, VA (Monday)

Sanders: MN, SC (Friday); SC, TX (Saturday); MN, OK (Sunday); CO, MN, MA (Monday)

Trump: TX, OK (Friday); AR, TN (Saturday); AL (Sunday); VA, GA (Monday)

Rubio: TX, OK (Friday); GA, AL, AR (Saturday); VA (Sunday); TN, GA, AR, OK (Monday)

Cruz: TN, VA (Friday); GA, AR (Saturday); OK, AR (Sunday); TX (Monday)

Kasich: TN (Friday); TN (Saturday); VT, MA (Monday).

On the trail today

Hillary Clinton begins her day campaigning in Atlanta, GA before holding events in South Carolina, including an evening rally with her husband in Columbia, SC… Bernie Sanders stumps in Minnesota and South Carolina… Donald Trump holds rallies in Fort Worth, TX and Oklahoma City, OK… Ted Cruz hits Tennessee and Virginia… Marco Rubio campaigns in Dallas and then Oklahoma…And John Kasich is in Tennessee.

Countdown to Dem South Carolina primary: 1 day

Countdown to Super Tuesday: 4 days