AMNA NAWAZ: There is a growing rift within the Republican Party over how, and if to assist Ukraine as its war against Russia enters its second year.

Lisa Desjardins takes a deeper look.

LISA DESJARDINS: In Ukraine today, life, death, and explosions on repeat in the battle for the eastern front.

But the future of this war and the people here now may depend on something new, a fast-rising political conflict.

REP. MARJORIE TAYLOR GREENE (R-GA): No money to Ukraine, and that country needs to find peace, not war.

(CHEERING AND APPLAUSE) STEVE BANNON, Former White House Chief Strategist: We are not a European power.

We are a Pacific power.

LISA DESJARDINS: Republicans, once defined as Cold War hawks distrustful of Russia, are quickly and sharply splitting over U.S. support of Ukraine.

And they're doing it in prime time.

TUCKER CARLSON, FOX News Anchor: Last week, we sent a questionnaire to every Republican presidential candidate, announced and potential, asking about Ukraine.

LISA DESJARDINS: FOX News host Tucker Carlson aiming to put Ukraine at the center of the 2024 GOP race.

Former President Donald Trump responded, saying: "Ukraine should expect little money, unless Russia keeps prosecuting or pushing the war."

Trump has long questioned the amount of funding for Ukraine and four Ukraine and how much Europe is contributing, as evidenced this week in Iowa.

DONALD TRUMP, Former President of the United States: If you look at the war, if you look at what's going on, we're spending about $150 billion, and they're at about $25 billion.

I would say that's not right.

LISA DESJARDINS: But now it appears Florida Governor Ron DeSantis, an expected presidential candidate, is staking out an isolationist position.

In his response to Tucker Carlson, DeSantis wrote: "While the U.S. has many vital national interests, becoming further entangled in a territorial dispute between Ukraine and Russia is not one of them."

That elicited this from Carlson.

TUCKER CARLSON: DeSantis is not a neocon.

LISA DESJARDINS: That's a shot at others, like former Vice President Dick Cheney or South Carolina Senator Lindsey Graham, who have seen a U.S. role replacing adversaries, in changing regimes.

This firmly places the two Republicans leading 2024 polls on the isolationist spectrum.

But others see opportunity for contrast, like former Vice President Mike Pence directly taking on DeSantis' words in a radio interview today.

MIKE PENCE, Former Vice President of the United States: The war going on in Ukraine right now is not a territorial dispute.

It is the result of an unprovoked war of aggression by Russia.

LISA DESJARDINS: Also loudly breaking with Trump and DeSantis on this is former South Carolina Governor Nikki Haley.

Last week in Iowa, an audience member interrupted her... NIKKI HALEY (R), Presidential Candidate: Look at how... MAN: Ukraine is not our ally.

Why are we... NIKKI HALEY: Oh, hang on.

LISA DESJARDINS: ... saying Ukraine is not an ally.

Haley responded that Ukraine is a staunch ally and: NIKKI HALEY: This isn't about starting war.

This is about preventing a war.

We need to make sure we prevent a bigger war from happening.

LISA DESJARDINS: As for other potential Republican presidential candidates, South Carolina Senator Tim Scott said that degrading Russia's military is of vital interest to the U.S. And Secretary of State -- former Secretary of State Mike Pompeo did not respond to Tucker Carlson's questions -- Amna.

AMNA NAWAZ: Our Lisa Desjardins reporting on this important topic.

Also joining us for more here in the studio is our Nick Schifrin.

But, Lisa, back to you for a moment.

When you look at this division among Republicans, what is driving this right now?

LISA DESJARDINS: I spent a good time talking to some ambitious Republicans who are out on the stump and who also are working with donors.

And that gave me an answer, that there really is a split between voters and donors in the Republican Party.

Let's look at where voters are.

In our latest "PBS NewsHour"/NPR/Marist poll, we asked, what about support levels for Ukraine?

You can see, among Republicans, 47 percent in that poll said, there's too much support, too much U.S. support.

And then you see the rest of Republican voters, somewhere between not enough and about right.

Now, that indicates there's a split among Republicans.

But what Republicans I talk to, Amna, are seeing is the trend here.

That 47 percent that don't want as much support for Ukraine, that's a huge leap, and the number keeps growing.

Why is that?

Well, some of the suspicions here, some of the -- talking to voters also today, they tell me that they just have a problem after the U.S. withdrawal from Afghanistan in trusting the current military leadership and that, overall, there is a sense that the U.S. has problems here at home that it needs to take care of, rather than dealing with things overseas.

Other Republicans, however, as you heard in that story, say, no, Ukraine is a critical battle line, it is about American values and about U.S. interests going forward.

AMNA NAWAZ: Lisa, obviously, any future funding to support Ukraine would have to go through members of Congress.

Is this debate, are these divisions influencing that decision, potentially?

LISA DESJARDINS: We're entering an absolutely critical few months in terms of us funding for everything ahead.

I think it's fair to say that the funding debate ahead of us for, let's say, for next four months is going to be potentially one of the most incendiary and unpredictable that we have seen in some time.

And key in that, key in deciding whether Ukraine will get more critical support, as they view it, from the U.S. or not will be the U.S. Senate.

Today, the number two Senate Republican, John Thune, was asked about Ukraine, and I want to play what he said.

SEN. JOHN THUNE (R-SD): There are lots of different opinions on the U.S. involvement in Ukraine.

But I think the majority opinion among Senate Republicans is that the United States has a vital national security interest there in stopping Russian aggression.

And that certainly the view I have.

LISA DESJARDINS: This will be a real test for Senate Republicans, because a lot of them represent red states.

They are under pressure.

Some lawmakers telling me today that, when they are out talking to voters, the greatest applause lines they get are talking about getting the U.S. out of involvement overseas.

So Senate Republicans, who generally do believe that Ukraine should be supported, will be tested, because, in order for Ukraine to get any money, they're going to need that support in the U.S. Senate.

Overall, Amna, I think you could say this is a real test about how you view Ukraine in the world, how you view Russia's role in the world, the U.S. role in the world, but also how Republicans view their own voters.

AMNA NAWAZ: So, let's talk more about that here in the studio with Nick Schifrin.

Nick, these divisions on how to view Ukraine are clearly emerging among the Republican candidates.

How does all of this align with the Republican foreign policy experts you speak with?

NICK SCHIFRIN: Yes.

No, we spoke to quite a few today and over the last few days.

And, as Lisa is reflecting, there is a split.

First of all, on the establishment, they not only argue that the war is worth it, but they argue that President Biden isn't waging enough war.

They want Biden to send more weapons, F-16, long-range rockets, so that Ukraine can win, avoiding, by the way, a longer war that would, of course, cost even more money.

And as you heard Senator Thune just there, they make these bigger ideological arguments.

Autocracy should not be allowed to steamroll democracy.

Stopping Russia protects NATO and also sends a message to China over Taiwan.

That is the same argument.

you hear from the administration, even today, Secretary of Defense Lloyd Austin, when asked about some of this Republican criticism.

LLOYD AUSTIN, U.S. Secretary of Defense: Ukraine matters.

It matters not to just Ukraine or to the United States.

It matters to the world.

This is about the rules-based international order.

It's about one country's ability to wake up one day and change the borders of its neighbor and annex its neighbor's sovereign territory.

NICK SCHIFRIN: And if that is the establishment argument, then there is the other one.

And that is the Republican base described to me from MAGA to Main Street to Wall Street to the working class.

They do not want to hear about another long war from the establishment, a war that cannot obviously be won, a war whose burdens these people think that they have to pay over these elite.

Number two, Ukraine is corrupt and in Russia's backyard.

Number three, why risk an escalation with a nuclear-powered Russia, who, by the way, was associated, of course, with President Trump's claim of a political hoax, when the real threat is, in fact, China, and we can't do both at the same time?

And what's interesting, going back to Ron DeSantis' statement, because DeSantis is multiple strands of this, right?

The part of this that Lisa highlighted, he started with this ultimate statement: "While the U.S. has many vital national interests, becoming further entangled in a territorial dispute between Ukraine and Russia is not one of them."

But he doesn't end there.

He adds this: "The U.S. should not provide assistance that could require the deployment of American troops or enable Ukraine to engage in offensive operations beyond its borders.

These moves would risk explicitly drawing the U.S. into the conflict and drawing us closer to a hot war between the world's two largest nuclear powers.

That risk is unacceptable."

That is an endorsement of President Biden's policy on long-range weapons and escalation.

It is also a rejection of the Republican establishment argument's against President Biden.

AMNA NAWAZ: Continuing to cover every angle of this important story.

Nick Schifrin and Lisa Desjardins, thank you to you both.