GEOFF BENNETT: Welcome to the "News Hour."

President Trump announced a dramatic shift in U.S.

policy on Ukraine today in New York City.

He previously suggested Ukraine would have to give up territory to make peace.

But today, he said the country could win back all its territory, which has been occupied or annexed by Russia since 2014.

The president made the announcement on social media after delivering the first speech to the United Nations of his second term.

As Nick Schifrin reports, the president's speech focused less on U.S.

leadership and more on what he believes the rest of the world is getting wrong.

NICK SCHIFRIN: Today, to an international community that doubts, but still desires U.S.

leadership, President Trump delivered a dark disparagement of global priorities.

DONALD TRUMP, President of the United States: I'm really good at this stuff.

Your countries are going to hell.

NICK SCHIFRIN: With that broadside, President Trump took his closed border vision global.

And U.S.

officials tell PBS "News Hour" the U.S.

will push to change 75-year-old international refugee laws.

Asylum seekers would have to claim protection in the first country they entered.

Asylum would be temporary.

And the host country would arbitrate the asylum case.

DONALD TRUMP: We have to solve the problem and we have to solve it in their countries, not create new problems in our countries.

NICK SCHIFRIN: And President Trump combined that criticism with the denigration of decades of efforts to combat what the scientific community judges an existential threat to the planet.

DONALD TRUMP: This climate change, it's the greatest con job ever perpetrated on the world.

I love the people of Europe, and I hate to see it being devastated by energy and immigration.

This double-tailed monster destroys everything in its wake, and they cannot let that happen any longer.

NICK SCHIFRIN: But much of Europe is more focused on war in Ukraine.

And, today, President Trump announced a major policy shift.

He wrote on TRUTH Social: "I think Ukraine, with the support of the European Union, is in a position to fight and win all of Ukraine back in its original form.

The original borders from where this war started is very much an option."

Russia's also been escalating inside of NATO.

Last week, three Russian jets flew within 10 miles of the Estonian Parliament.

And the week before that, an unprecedented number of Russian drones flew deep into Poland, whose prime minister, Donald Tusk, vowed not to let it happen again.

DONALD TUSK, Polish Prime Minister (through translator): We are ready for any decision aimed at destroying objects that might pose a threat to us, for example, Russian fighter jets, if they violate, for example, fly over our territory.

But I also need to be absolutely certain, and I won't elaborate on this point, that all allies will treat this in exactly the same way as we do.

NICK SCHIFRIN: Today, President Trump agreed.

QUESTION: Mr.

President, do you think that NATO countries should shoot down Russian aircraft if they enter their airspace?

DONALD TRUMP: Yes, I do.

NICK SCHIFRIN: The other war that has dominated this week's discussion is Gaza, where today much of Gaza's city is a shell of itself and mostly a ghost town after an exodus of Palestinians ahead of an Israeli assault.

Today, President Trump met with Arab and Muslim leaders to discuss the day after the war in Gaza.

DONALD TRUMP: This is my most important meeting.

I have had important meetings.

I don't want to insult anybody -- that we have met with.

We have met with -- I had 32 meetings here.

But this is the one that's very important to me, because we're going to end something that should have probably never started.

NICK SCHIFRIN: President Trump always mixes the policy with the personal, and today said, despite targeting Brazil with tariffs, would meet President Lula for the first time next week.

DONALD TRUMP: He liked me.

I liked him.

(LAUGHTER) DONALD TRUMP: But if you -- and I only do business with people I like.

I don't -- when I don't like them -- when I don't like them, I don't like them.

NICK SCHIFRIN: President Trump did not like that he and the first lady had to walk up a broken escalator, or that his teleprompter was at first not prompting.

DONALD TRUMP: I can only say that whoever's operating this teleprompter is in big trouble.

(LAUGHTER) NICK SCHIFRIN: After those jokes, he blasted and blamed the U.N.

for migration.

DONALD TRUMP: The U.N.

is supposed to stop invasions, not create them and not finance them.

NICK SCHIFRIN: But with U.N.

Secretary-General Antonio Guterres, President Trump tweaked his tone.

DONALD TRUMP: Our country is behind the United Nations 100 percent.

And I think the potential of the United Nations is incredible, really incredible.

NICK SCHIFRIN: But the U.N.

champions global cooperation and human rights, and, tonight, the White House called the president's speech -- quote -- "a powerful rebuke to the destructive globalism that has fueled endless conflict and chaos around the world" -- Geoff.

GEOFF BENNETT: And, Nick, take us back to the president's statement on TRUTH Social about Ukraine.

How different is that from what he said and why is that so significant?

NICK SCHIFRIN: It is very significant.

In fact, President Zelenskyy was just speaking to reporters, including our producer Sonia Kopelev, and Zelenskyy said -- quote -- this is a -- quote -- "big, big shift."

And I wanted to take you back to that message that the president posted, because he talked about that Ukraine will -- could win back all of its original form.

So let's look at the map.

In 2014, Russia invaded and annexed Crimea, which still is U.S.

policy as part of Ukraine.

After that annexation, they then invaded Eastern Ukraine.

And, of course, in 2022, the full-scale invasion has pushed further into Eastern Ukraine and Southeast Ukraine.

So look at that map.

You have got not only Crimea, but all the way up to parts of Kharkiv in the northeast of Ukraine, some 18 to 19 percent of the country.

Up until today, President Trump has been very dismissive of the idea that Ukraine could somehow re-seize all that territory or, frankly, even get back any of that occupied territory, let alone its original form, which would include Crimea.

And senior officials have repeatedly said that there is no military solution that Ukraine can even dream of to try and get back that territory.

So the fact that he is saying that after a meeting with Zelenskyy, after meeting Europeans today that Ukraine could achieve that back on the battlefield is really a fundamental shift.

We don't know the specifics, but it's a fundamental shift.

At the same time, Geoff, the message ends this way: "I wish both countries well.

We will continue to supply NATO -- weapons to NATO for what they want to do with them.

Good luck to all."

President Trump at the same time is suggesting he's a little bit washing his hands of this conflict.

We will see how the policy evolves, Geoff.

You saw President Trump there still promising to send American weapons to NATO, via NATO to Ukraine, but, the bottom line, a fundamental shift for how President Trump at least sees the future of Ukraine itself and what it can achieve on the battlefield, Geoff.

GEOFF BENNETT: Nick Schifrin reporting from the U.N.

General Assembly.

Nick, our thanks to you.

NICK SCHIFRIN: Thank you.