The evening leaves him with a strong moral case for the Republican nomination, and everyone trying to work out what the heck he'll actually do with it. Expect a more moderate tone. Trump, believe or not, is showing signs of political sophistication.
The lingering GOP argument against a Trump nomination is that a) he remains unpopular with the wider electorate and that b) the delegate count is still stacked against him. It's true that he heads into tougher, more western terrain after the Acela primaries; it's also true that Ted Cruz and John Kasich have forged an alliance to stop him. They make an unlikely Butch Cassidy and the Sundance Kid, but they're determined to go down with a fight.
They'll probably lose. True, Trump is a surprisingly unpopular front-runner who hasn't enjoyed huge majorities in primaries -- until now. The argument used to be that as the field narrowed and the GOP organized a counteroffensive, Trump would hit a natural ceiling of support and start losing.
The opposite appears to be true: the narrower the race, the better he does. Aside from sweeping all five states on Tuesday, he won every single demographic in most of them. He even did well
in the Philadelphia suburbs, areas that often function as a predictor of how a nominee will do in November. His support has proven to be as wide as it is deep, undivided by class, gender or income. There is no evidence that the counter revolutionary alliance is popular enough -- or Trump unpopular enough -- to stop him.
By the time that the Republicans gather in Cleveland, they are going to have to face up to an uncomfortable truth. Yes, Trump's victory has been built largely on pluralities. But no, the Republican Party has not been able to find an alternative that Republican voters are prepared to endorse. Trump is nominee almost by default.
Which leaves us with two questions. First, how will he navigate the convention? His victory speech heralded a change in tone. Lots of promises to unify and heal and reach out to the disgruntled, even a few nice words about the media. It was "moderate energy." Behind the scenes, Trump's campaign has promised to hire speechwriters
and he's practicing with a teleprompter.
Evidence is growing that the establishment is prepared to take a second look. Reince Priebus, the GOP chair with the hardest job in the Western world, has warned conservatives that there will be no alternative
to the nominee. So there's every likelihood that the convention could reach a peaceful accord; the GOP might yet rally around its front-runner.
That said, you can never be sure with Trump. The man is unpredictable. For that reason, the answer to the second question -- how will he run in the fall? -- remains equally unclear. It is said that he's tacked a little to the left recently.
He has, supposedly, argued that transgender people should be able to use the restrooms they want and that the Republican platform should support legal abortion in certain instances. But are these positions the product of strategic thinking or Trump finding his feet as a new arrival to the world of conservatism?
Very shortly after he questioned North Carolina's bathroom bill, Trump said that it was actually a state issue and the federal government should stay out. And his views on abortion
have vacillated from suggesting women could face punishment to now being a little more liberal.
Moreover, even if Trump's private instincts are socially tolerant, the Democrats won't define him that way in the fall campaign. In her Tuesday night speech, Hillary Clinton hammered away at the social issues and promised to "break down barriers" rather than "build walls," asserting that "love trumps hate."
After delivering each of these slogans, Clinton did that weird thing she does where she nods at what she just said as though she wasn't the one saying it. Her visuals are often a little baffling, but her message is utterly disciplined: Clinton will fight Trump on Trump's reputation as a bigot rather than the reality of Trump as a complex man without a clearly defined politics.
Clinton, however, had better watch out. The scale of Trump's latest victories indicates that he does have the potential to break through a wall of negative media, hit the economic issues effectively and drag his opponents down with sheer strength of will.
This campaign cycle is slowly evolving from a narrative of Trump as a "surprise winner" to Trump as a potential nominee. The votes haven't dried up as a result; there's still a lot of enthusiasm for him out there.
When Trump described Tuesday as his "biggest night," he was probably right.