AMNA NAWAZ: A European official tells "PBS News Hour" that Ukraine and its European allies will present new edits to an American peace proposal by tomorrow.

The U.S.

has been pursuing a solution to the war in Ukraine and recently highlighted those efforts as part of its new national security strategy that shifts historic U.S.

language on Europe.

Nick Schifrin examines that document, but begins his report in Eastern Ukraine, where Kyiv is struggling to hold the line.

NICK SCHIFRIN: In Eastern Ukraine, it's a fight against time.

Soldiers patrol the city of Kostyantynivka under siege and under nets designed to protect from Russian drones.

The battle is now street to street.

Nearby Russian soldiers post their own drone videos hunting Ukrainian positions; 32-year-old Dmytro is like every soldier here, exhausted, but determined to resist military and diplomatic pressure.

DMYTRO, Ukrainian Armed Forces (through translator): I count every centimeter of the motherland as important.

And we don't plan to give it up just like that.

NICK SCHIFRIN: Thirteen hundred miles away today, Western European leaders who share that determination rallied around Ukrainian President Volodymyr Zelenskyy.

Last week, these leaders allegedly said in private the U.S.

might betray Ukraine.

Today, they tied their own security to Ukraine's.

FRIEDRICH MERZ, German Chancellor: We are still and remain strongly behind Ukraine and giving support to your country, because we all know that this -- the destiny of this country is the destiny of Europe.

I'm skeptical about some of the details which we are seeing in the documents coming from the U.S.

side.

NICK SCHIFRIN: That skepticism over a U.S.

peace proposal and security guarantee negotiated with Ukraine.

A European official tells "PBS News Hour" the U.S.

is still pushing Ukraine to give up the portion of the Donbass region that it controls and that Russia has failed to capture through 11 years of war.

That territory would be internationally recognized as Russian, but demilitarized.

On that, Zelenskyy said there was no agreement, telling Bloomberg today -- quote -- "There are visions of the U.S., Russia and Ukraine, and we don't have a unified view on Donbass."

Zelenskyy says he needs the U.S.

and Europe to work together.

VOLODYMYR ZELENSKYY, Ukrainian President: Unity between Europe, Ukraine, and the United States, because some things which we can't manage without Americans, things which we can't manage without Europe.

NICK SCHIFRIN: But the White House's new national security strategy flips the traditional script on Europe.

It reads: "It is a core interest of the United States to negotiate an expeditious cessation of hostilities in Ukraine in order to stabilize European economies, prevent unintended escalation or expansion of the war, and reestablish strategic stability with Russia."

And it warns of "European civilizational erasure, the larger issues facing Europe include activities of the European Union and other transnational bodies that undermine political liberty and sovereignty.

It is far from obvious whether certain European countries will have economies and military strong enough to remain reliable allies."

This weekend, Moscow agreed.

DMITRY PESKOV, Spokesman for Vladimir Putin (through translator): The corrections that we see correspond in many ways to our vision.

So there is reason to hope this could be a modest guarantee, that constructive joint work on finding a peaceful settlement for Ukraine, at a minimum, can continue.

NICK SCHIFRIN: For perspective on the White House's national security strategy, we get two views.

Heather Conley was deputy assistant secretary of state for European affairs during the George W. Bush administration and is a nonresident fellow at the American Enterprise Institute, a Washington think tank.

And Dan Caldwell was an adviser to Defense Secretary Pete Hegseth.

He was in the Marine Corps and has worked for a member of Congress and think tanks that focused on veteran and defense issues.

Thanks very much to both you.

Welcome to the "News Hour."

I just read you in that story the language on Europe, calling for strategic stability with Russia, accusing the E.U.

of undermining political liberty and warning of European civilizational erasure and that Europeans might not be strong enough to remain reliable allies.

Dan Caldwell, is that the right language?

DAN CALDWELL, Former Adviser to Defense Secretary Pete Hegseth: Well, I just want to point out the document says something else.

It says that Europe is strategically vital to the United States.

The document makes clear that we want to be partners with Europe.

However, Europe can't be effective partners to us if they continue their economic, military and cultural decline.

If they keep going down the path that they are, they will not be partner.

They will be dependents and free riders, and that's in no one's interest.

On the question of Russia and pursuing strategic stability, I think that's in the interest of the United States and Europe, because instability leads to a risk of a war.

And a war with a nuclear power like Russia is, again, in no one's interest.

NICK SCHIFRIN: So, Heather Conley, take that thought on, European decline, but also strategic stability is in U.S.

interests with Russia.

HEATHER CONLEY, American Enterprise Institute: I agree with Dan the document is clear we are concerned about Europe's economic competitiveness.

Certainly, many American presidents have been concerned about low European defense spending.

But President Trump, in the letter before the security strategy, says, hey, look, they have agreed to do 5 percent.

It is exactly, though, the message about the cultural erasure, that Europe's democracies, they have political parties.

And we're putting our thumb on particular parties that the current administration agrees with.

On strategic stability, it is Russia that over the past 15 years has violated basically every international arms control agreement that we have had.

And even the Trump administration has acknowledged those violations.

To achieve strategic stability is to do that with our allies, to present, again, peace through strength, the strength of a strong nuclear deterrence, a strong military defense.

And then we can come to the table.

But Russia has to be transparent, and they have been anything but transparent.

NICK SCHIFRIN: So, Dan Caldwell, strategic stability with Russia with Europe, rather than despite Europe, respond to that.

DAN CALDWELL: Well, again, in the document, it actually gets into this as well too, is the way to achieve that is, first and foremost, got to end the Ukraine war.

And it's going to be a messy process.

And it's not going to be a peace that ultimately gives Ukraine everything it wants.

But it's going to be a decent peace and give a peace that hopefully allows Ukraine to exist as a sovereign country with a path to prosperity.

So I think that's important.

But also, too, again, as the document points out, is that Europe has tremendous power and that they can do a lot more themselves to ultimately deter and contain Russia.

And so that's an important part of this, too, is that they need to take up more of the burden in dealing with the security challenges in their own backyard, primarily those dealing with Russia.

NICK SCHIFRIN: Heather Conley, this is a fundamental difference between the United States government that now sees the future with Russia as strategically stable and a Europe that generally sees Russia as the adversary beyond the war in Ukraine, right?

HEATHER CONLEY: Exactly.

And this is how this war ends or how it temporarily is paused, that is what's going to create the strategic stability.

And if the United States, rather than being, again, on the side of our European allies pressing for sovereignty and territorial integrity, something that the national security strategy continues to emphasize -- well, Russia has violated that for the last 11 years, creating the instability in Europe.

Europe is stepping forward.

They're doing more.

But if we're the bridge, if we're moderating between these two, that means we are not firmly on the side of sovereignty, territorial integrity, and standing with our allies.

NICK SCHIFRIN: Let me switch to Latin America here, because a significant portion of the document is dedicated to Latin America and the United States' southern border.

And it includes this language, a reference to 19th century opposition to European colonialism in Latin America -- quote -- "The United States will reassert and enforce the Monroe Doctrine to restore American preeminence in the Western Hemisphere."

And this now is a reference to China and Russia: "We will deny non-hemispheric competitors the ability to position forces or other threatening capabilities or to own or control strategically vital assets in our hemisphere.

This Trump corollary to the Monroe Doctrine is a commonsense and a potent restoration of American power and priorities."

Dan Caldwell, what's your response to that language?

DAN CALDWELL: Ultimately, at the end of the day, there are more vital national interests in the Western Hemisphere than there are anywhere else in the world.

What happens in our own hemisphere is, frankly, more important than who controls the Donbass or who controls the... (CROSSTALK) NICK SCHIFRIN: Eastern Ukraine.

DAN CALDWELL: Yes, and who controls the Anbar Desert.

NICK SCHIFRIN: In Western Iraq.

DAN CALDWELL: Yes.

So, I think that it is a great thing that this administration is making clear that the Western Hemisphere is our top priority.

Now, again, I want to also point something out.

That does not mean that every single national security resource, whether it's a diplomatic efforts, whether it's a military efforts, other parts of soft power, is going to be solely focused on the Western Hemisphere.

And, again, I think the document makes that clear.

What I have been disappointed to see is, is that that's been kind of the framing that you have seen leading up into the release of this document and the coming release of the national defense strategy.

And so, again, I -- for most of our history, the Western Hemisphere was where we were mostly focused.

And the Monroe Doctrine was our most important foreign policy doctrine.

And, over time, as the world has changed, the United States has had to do different things.

But because of where we focused and because we have been distracted by things overseas that aren't necessarily core to our safety and prosperity, I do think that we have neglected the Western Hemisphere too much.

And I'm glad to see the president change that.

NICK SCHIFRIN: Heather Conley, we have been distracted, as Dan Caldwell just said, is that right?

HEATHER CONLEY: Well, I think, for the last 20 years, yes, we have been overly concentrating on the Middle East and that, in some ways, the first Trump administration's 2017 national security strategy reset that balance and said we have great power competition.

Our adversaries are Russia and China.

This strategy takes us in a very different direction.

It returns us back to the 19th century to spheres of influence.

But I think what it doesn't tell us is what those modern national security threats are.

The document is silent on North Korea's construction of intercontinental ballistic missiles that can reach the United States or Russian hypersonic cruise missiles.

That's why we're building Golden Dome, which is prominent in the doctrine.

So, when we have the sphere of influence, that's exactly why the Kremlin just said this is wonderful, because they want to create a sphere of influence.

So does China.

NICK SCHIFRIN: Heather Conley, Dan Caldwell, we will have to leave it there.

Thanks very much to you both.

HEATHER CONLEY: Thank you.

DAN CALDWELL: Thank you.