JUDY WOODRUFF: Donald Trump has now cemented his status as the Republican presidential standard=bearer in the fall. He clinched the delegates needed for the nomination today, even as he took fire from the man who holds the job now.
John Yang begins our coverage.
DONALD TRUMP (R), Republican Presidential Candidate: The folks behind me got us right over the top, from North Dakota.
JOHN YANG: Literally backed by his North Dakota delegates, Donald Trump celebrated his status as the now certain nominee at a news conference in Bismarck.
The Associated Press reports that one of those delegates gave him the 1,237 vote he needs to win on the first ballot at the Republican Convention. It came on the same day that President Obama used his own news conference at the G7 Summit in Japan to say that world leaders are worried about a Trump presidency.
PRESIDENT BARACK OBAMA: They're rattled by him, and for good reason, because a lot of the proposals that he has made display either ignorance of world affairs or a cavalier attitude or an interest in getting tweets and headlines.
JOHN YANG: Trump dismissed the president's criticism.
DONALD TRUMP: Many of our — the countries in our world, our beautiful world, have been absolutely abusing us and taking advantage of us. So, if they're rattled in a friendly way, we are going to have great relationships with these countries.
But if they're rattled in a friendly way, that's a good thing, John, not a bad thing.
JOHN YANG: Even as he clinched the nomination, Trump faces more turmoil within his campaign staff. His national political director, Rick Wiley is out, just six weeks after he was brought on to help professionalize the Trump effort.
In a statement last night, the campaign insisted that Wiley was always a short-term hire.
Trump seemed delighted by the fact that his nomination, once thought improbable, was decided before the Democrats.
DONALD TRUMP: And here I am watching Hillary fight, and she can't close the deal.
JOHN YANG: In fact, Hillary Clinton is within 78 delegates of locking up her party's nomination, but a new poll shows her in a virtual tie with Bernie Sanders in the California primary less than two weeks away.
Today, Clinton reacted to Trump going over the top.
HILLARY CLINTON (D), Democratic Presidential Candidate: That means an unqualified loose canon is within reach of the most powerful job in the world.
JOHN YANG: Clinton also dismissed a State Department watchdog report that found she violated policy by using a private e-mail server as secretary of state. She told a Univision affiliate last night, "I will continue to be open, and it's not an issue that's going to affect either the campaign or my presidency."
JIMMY KIMMEL, Host, "Jimmy Kimmel Live": Here's the question from Bernie.
JOHN YANG: Sanders, meanwhile, used late-night talk show host Jimmy Kimmel to challenge Trump to a debate. Trump says he'd do it for a price.
DONALD TRUMP: Oh, I would love to debate Bernie. He's a dream. Well, I said — and I said last night on Jimmy's show — the question that was posed, I said I would love to debate him, but I want a lot of money to be put up for charity. So, what we will do is, if we can raise for by women's health issues or something.
QUESTION: If you raise $10 million, you will get on a debate stage with Bernie Sanders?
DONALD TRUMP: I would love to, yes.
JOHN YANG: Today, Sanders says he can't wait.
SEN. BERNIE SANDERS, Democratic Presidential Candidate: And I'm very excited about it, and I think we're going to st going to rent out the largest stadium you have here in California.
JOHN YANG: Sanders had asked Clinton to debate, but she declined.
For the "PBS NewsHour," I'm John Yang.
JUDY WOODRUFF: We will focus on how foreign leaders are reacting to the rise of Donald Trump after the news summary.