Now comes the hard part.
Now comes the part where Donald Trump has to appeal to everyone in the U.S.
Trump will rack up lots of easy votes in the fall with his rabid fan base — older grumpy white males and their spouses who want change but don't really know or care if Trump is a Republican or a Democrat.
But voters who want to make America great again by being mean to Latinos or by putting tariffs on air-conditioners and iPhones won't add up to a majority.
If he wants to become president, Trump has to mend a lot of fences, say a lot of mea culpas and learn a bunch of important political and economic things.
Like manners. Like humility. Like gravitas.
And like making nice with the Bush/Cruz/Kasich conservatives he's been insulting and demeaning with sophomoric cheap shots for the last year.
The presumptive Republican nominee should start his political fence-repair work by trying to win over a few million women voters.
It won't be easy. Three-fourths of women think he's a piece of dirt and wouldn't vote for him if he was married to Hillary.
I don't know what it'll take, or even if it's possible, but somehow Trump has to prove that deep down he is not the sexist boor he's been playing on TV.
I know one thing he should not do — attack Hillary for enabling her lecherous husband Bill and attacking the women who say they were accosted by him.
That didn't work in the 1990s. All it did was make independent women vote for Hillary or stay home.
Trump's long march to victory over the Republican political establishment has been an amazing thing to watch — kind of like a TV miniseries where the bad guy never gets taken down in the end by the good guys.
For a year he's made fools of the media pundits and mincemeat of the professional politicians of his party.
He's the un-politician who broke all the rules of the primary game and won. That's a big reason he got so many votes in so many states.
We wanted a Washington outsider. What we got was a salesman. He did and said whatever he had to do to make the sale to the Republican electorate.
As I tweeted earlier this week, the GOP is no longer the Party of Reagan, it's the Party of Trump.
Where he takes Republicans from here is anyone's guess, but it's probably going to be one of the wilder political rides in modern American history.
If America gets lucky, Trump will hit his head on a tree limb and when he wakes up he'll be a real conservative who runs on a platform of slashing government spending and abolishing the IRS.
Or maybe he'll hire some economists who can teach him why tariffs are bad for America because they punish consumers and not corporations.
Or maybe someone will explain to him why building a 300-foot wall on the Mexican border and rounding up 11 million illegal immigrants is not how a free — and great -- country should do immigration reform.
Trump will need everybody he can get to defeat Hillary.
Who he picks for vice president will be interesting, but it won't really matter because we know people don't vote for a president because they like the VP choice.
It could be Rubio or Kasich, because that would help him in Florida and Ohio. It could be a Latina woman like Nevada Governor Susana Martinez.
Or, knowing Trump, he might go outside the box and name one of his business partners we've never heard of. No one knows where he's going to go until he goes there.
There is one thing I know for sure. If Trump becomes president he won't be able to treat the members of the G-7 or the G-20 the same way he treated the GOP 17.
Michael Reagan is the son of President Ronald Reagan, a political consultant, and the author of "The New Reagan Revolution" (St. Martin's Press). He is the founder of the email service reagan.com and president of The Reagan Legacy Foundation.