Donald Trump shrugged off continuous attacks from his rivals, damaging stories in the press, and regular confusion over his own policy platform to end the week where he began: the front-runner for the Republican nomination.
At the same time, Senator Marco Rubio, the candidate many in the establishment pegged as their champion, appears to be on life support. His rapid decline leaves Texas Sen. Ted Cruz, a hardline conservative loathed by many party insiders, as the GOP'S last best alternative to Trump.
But while Cruz won Idaho, Trump easily won Michigan and Mississippi — the two biggest delegate prizes of Tuesday's contests — and was projected to win the Hawaii caucus. In doing so he once again dashed rivals' hopes that their efforts to drag down his campaign might finally be yielding fruit.
"I don't think I've ever had so many horrible things said about me," Trump stated in a press conference on Tuesday night.
The races were a heat check ahead of crucial winner-take-all races in Ohio and Florida. The results suggest that Trump is well positioned to compete in both states. If they go his way, his rivals will have few paths to defeating him, short of a long-shot effort to narrowly deny him a delegate majority and then somehow oust him in a contested convention in July.
Making Trump's path to Florida easier: The ongoing collapse of Rubio, who suffered through a brutal night on Tuesday ahead of his home state primary.
In Michigan, a state Rubio's campaign would likely have considered prime territory just weeks ago, he failed to crack double digits. The results were even worse in Mississippi, where he finished in fourth with just 5 percent with 92 percent of precincts reporting.
It was a major shift from Super Tuesday just one week earlier, when Rubio closely battled Cruz for second place in similar southern states. In Michigan Rubio finished well behind third-place Ohio Gov. John Kasich, who has shown little appeal in the region.
Rubio's implosion could not come at a worse time, both for his own campaign and for the broader anti-Trump effort led by former Republican nominee Mitt Romney.
Romney, who recorded robo-calls for Rubio and Kasich in Michigan, urged Republicans in a speech last week to vote for the senator in Florida and Kasich in Ohio in order to deny Trump a delegate majority. Now Rubio looks like a zombie candidate as the race turns to his own state, where many voters have already cast early ballots.
After largely avoiding clashes with Trump for months, Rubio turned his campaign into a vehicle for an all-out war on the front-runner over the last several weeks. In speeches and debates, he derided Trump as a "con artist" and "unelectable," accused him of ripping off students with his Trump University program, and mocked his hair, his tan, and the size of his anatomy.
The results, combined with weak performances in four states on Saturday, suggested that his kitchen sink strategy against Trump backfired big time. Heading into Tuesday night, Rubio had won just two contests: Minnesota and Puerto Rico.
Even before the latest races, Rubio had already started to acknowledge that he was unlikely to win the nomination without forcing a contested convention.
"I don't think anyone has a clear path to 1237 delegates," Rubio said in Kissimmee, Florida, Tuesday morning. "So buckle up your seat belts — this ride has got a few more tricks and turns."
Assuming he stays in the race through Florida, Rubio will have significant help from outside the campaign for his last stand. Republican donors have poured over $8.3 million into a variety of super PACs that are carpet bombing Trump with attack ads in Florida — far more than Trump's $1.7 million in ad spending.
For Cruz, Rubio's staggered position presents an opportunity to knock his rival out of the race quickly, and then hope he can sideline Kasich to force a one-on-one contest against Trump.
Cruz is campaigning in Miami on Wednesday and a super PAC supporting him has announced it will run several different attack ads against Rubio this week.
There is some polling evidence, including a new NBC/WSJ survey of GOP voters released on Tuesday, that Trump is vulnerable if the race shrinks to two people. Anti-Trump Republicans don't have time to slowly wear him down, however. They need Trump to fall apart — and fast — to have any hopes of stopping him.
As it stands, even their most optimistic scenarios at this point assume a brutal July convention that would likely shatter party unity just as the general election begins. Whether or not they manage to defeat Trump at this point, the damage Trump's campaign has already done to the GOP's present incarnation is catastrophic. Whatever party crawls out of the smoking wreckage of the primary will not be the same one that entered it.