Donald Trump did what he needed to do tonight, scoring decisive victories in Michigan and Mississippi. Trump has always been strong in the South (except for Texas), and fading there would have been catastrophic. Michigan, the place where the Reagan Democrats were first " discovered " by the national media, was a crucial test for his candidacy, testing whether he could really win disaffected union members and workers. Trump delivered in both places.

Here's the takeaway:

There is no Trump collapse. Trump's support held up during a week of utterly brutal assaults against him from both the Left and the Right. In open primaries, Trump is formidable and proved his ability to grow the party and attract Reagan Democrats. In closed primaries, Cruz retains the advantage. The larger the number of eligible voters, the worse he does. Once again, Trump lost late deciding voters. Marco Rubio is almost finished. Cruz has the advantage in the upcoming Western primaries (Montana, Utah, Wyoming). In the northeast, he trails in polls but these states are closed primaries.

Trump came painfully close to securing all of Mississippi's delegates but missed by only a few points. He also won easily by double digits in Michigan, defying predictions of a Kasich surge that would somehow shock him at the last minute.

Meanwhile, Ted Cruz, who has repeatedly bragged about his ability to win Reagan Democrats, showed no crossover appeal. He can't win independents or crossover Democrats. However, he scored a large victory in Idaho, winning decisively among Mormons there. Cruz is right that conservatives (outside the South) are coalescing around him. However, there aren't many of them in states like New York or California.

Of course, both Michigan and Mississippi are open primaries, where Trump does best. Idaho was a closed primary. And there, despite polls showing Trump in the lead by double digits, Cruz was able to win there.

Marco Rubio has been reduced to being a spoiler for John Kasich as his sad candidacy limps towards its conclusion. Rubio will make his last stand in his home state of Florida, in the critical winner take all primary. Polls show Rubio trailing, though by how much is in dispute.

This Thursday is another Republican debate. All Trump needs to do is turn in a competent performance to reassure Florida voters that he can be trusted with their votes. As Cruz is targeting Rubio in Florida, Trump simply needs to hold on to his lead for another week to grab all of Florida's 99 delegates. Florida is a closed primary, but Rubio is falling apart and it is hard to see Cruz pulling ahead in any scenario.

Even better for Trump, the critical Ohio primary, another winner take all contest, is an open primary. If he can win these states, he has a path to the nomination.

Trump struck the right tone at the press conference following his victory in Michigan. He called Mitt Romney a "nice guy" while sarcastically thanking him for helping turn out supporters. He jokingly gave credit to "little Marco" for calling Ted Cruz a liar. Basically, he was restrained and semi-magnanimous, while still retaining his image as the alpha of the GOP. He even called for party unity.

Trump's press conference featured a host of Trump products, including Trump wine, water, and steaks. Trump energetically defended his company and even promised to reopen Trump University someday.

Some reporters snarked that this turned the press conference into an infomercial. But really, it was Trump defending his brand, and therefore, himself and his own image of competence, which is at the heart of his campaign. Trump's great strength, and weakness, as a candidate is that he tries to defend everything at once.

In theory, this shouldn't work. But it worked again tonight.