Ukraine joins the North Atlantic Treaty. Or Ukraine goes nuclear. That’s the choice President Zelensky gave Donald Trump at their meeting last month at New York.

“In a conversation with Donald Trump, I said: ‘This is our situation,’” Mr. Zelensky told the European Council last week. “What way out do we have? Either Ukraine will have nuclear weapons, which for us will be a defense, or we’ll need to have some sort of alliance.”

It was the first time since Russia’s invasion of Ukraine that Mr. Zelensky talked publicly about Ukraine  going nuclear. This fall, Ukraine is feeling pressure from all sides. 

Russia, at the cost of tens of thousands of casualties, has won several small cities in Ukraine’s southeast. Two weeks ago, Mr. Zelensky visited Washington and other NATO capitals. However, he did not come home with what he wanted: an invitation and a timetable for Ukraine to join NATO.

Yesterday, Russia’s Duma ratified a strategic partnership agreement between Russia and North Korea. Hours later, Ukrainian intelligence reported that North Korean soldiers arrived in Russia’s Kursk region to fight alongside Russian troops.

In America, Trump’s election could threaten aid to next year from the United States, Ukraine’s largest supporter. Since Russia’s invasion in February 2022, the Congress has approved five Ukraine aid bills, totalling $175 billion. It is unclear if the Congress elected next month will approve new aid next year.

Many Trump voters are skeptical of continued aid. In a nationwide poll conducted two weeks ago for Newsweek, only 21 percent of Trump supporters said Washington should maintain support for Ukraine. 

A larger group of Trump voters, 26 percent, said U.S. support should stop now. By contrast, 53 percent of Vice President Harris’s voters said Washington should maintain the aid. Only six percent want the aid stopped.

Asked if defense of Ukraine is “vital” to American interests, only 34 percent of Trump voters said yes. By contrast, 66 percent of Ms. Harris’s voters said yes. The poll was conducted by Redfield & Wilton Strategies. 

“Donald Trump heard me,” Ukraine’s president said in Brussels.  “He said you have a just argument.” Trump has not commented on that aspect of their conversation last month at Trump Tower.

However, President Putin immediately bridled at Ukraine’s leader threatening to go nuclear. “This is a dangerous provocation,” he told journalists the next day. “Any step in this direction will be met with a corresponding reaction.”

“It is not difficult to create nuclear weapons in the modern world,” Mr. Putin continued. “I do not know whether Ukraine is capable of doing it now. It is not so easy for Ukraine of today, but in general there is no great difficulty.”

While much of the world has forgotten, or never knew, the two leaders know that from Ukraine’s independence in 1991 until 1994, Ukraine was the third largest nuclear power in the world. 

As part of the breakup of the Soviet Union, Ukraine inherited 33 nuclear capable bombers, 176 intercontinental ballistic missiles and about 1,800 strategic nuclear warheads. 

Under heavy pressure from Washington and Moscow, Ukraine sent all the warheads to Russia and destroyed or sent to Russia all the bombers and missiles.

In exchange, Ukraine got a piece of paper, the 1994 Budapest Memorandum. The signers, America, Britain, Russia and Ukraine, agreed to respect Ukraine’s internationally recognized borders. 

Before the signing, international relations theorist and University of Chicago professor John Mearsheimer predicted in a Foreign Affairs essay, “The Case for Ukrainian Deterrent,” that without nuclear weapons, Ukraine would be subject to aggression by Russia. Thirty years later, Russia occupies almost 20 percent of Ukraine.

One of the signers, President Clinton, has regrets. “I feel a personal stake because I got them to agree to give up their nuclear weapons,” the former president told Irish broadcaster RTE last year. Referring to Ukrainians today, he said: “None of them believe that Russia would have pulled this stunt if Ukraine still had their weapons.”

“I knew that President Putin did not support the agreement President Yeltsin made never to interfere with Ukraine’s territorial boundaries — an agreement he made because he wanted Ukraine to give up their nuclear weapons,” Mr. Clinton added. “I feel terrible about it because Ukraine is a very important country.” 

Later, in 2010, at the Obama-era Nuclear Security Summit in Washington, Ukraine agreed to get rid of its stockpile of highly enriched uranium. While not weaponized, this could have been used to build nuclear bombs. 

Ukraine likely retains equipment needed to enrich its nuclear reactor products into weapons-grade nuclear material. Before 2022, Ukraine relied on nuclear power for half of its electricity.

On the international scene, Russia’s violation of the Budapest Memorandum delivered a serious blow to the cause of nuclear disarmament. North Korea has ignored a series of UN sanctions to build an arsenal of about 50 nuclear bombs. Israel may be poised to knock out Iran’s nuclear facilities. 

In Ukraine, nuclear disarmament regrets started in 2010 when Russia occupied Crimea and much of Ukraine’s Donbas. “We gave up nuclear weapons because of this agreement. Now, there’s a strong sentiment in Ukraine that we made a big mistake,” a Ukrainian parliamentarian, Pavlo Rizanenko, told USA Today at the time. “If you have nuclear weapons, people don’t invade you.”

A few hours after making his “NATO or nuclear” speech, Mr. Zelensky walked back his stance, telling reporters in Brussels: “What I meant is that today: there is no stronger security guarantee for us besides NATO membership.”

At Kyiv, a Foreign Ministry spokesman, Heorhii Tykhyi, refuted a report in Germany’s Bild newspaper that Kyiv officials claim they can build a bomb within weeks. He said: “We officially deny the insinuations of unnamed sources in the Bild publication regarding Ukraine’s alleged plans to develop weapons of mass destruction.”

On NATO admission, NATO member nations voted last June to say Ukraine is on an “irreversible” path toward membership. They just did not say how long it will take to travel that path. A formal invitation to join would set the clock ticking. Ukraine was first promised membership in 2008.

“Ukraine will be the 33rd member,” NATO Secretary General Mark Rutte assured reporters last week in Brussels. “Maybe someone else will come out ahead of them. But Ukraine will be a member of NATO in the future.”

European newspapers speculate that if Vice President Harris wins the election, President Biden would be tempted to burnish his historical legacy by extending the invitation to Ukraine. 

Full membership would only happen after the war ends and borders are agreed upon. One model is West Germany, which joined NATO in 1955. At the time, Soviet troops occupied the eastern 30 percent of Germany.

Mr. Zelensky remains defiant. Tuesday, he appeared on Ukrainian TV for his nightly talk to the nation. He was wearing a black T-shirt emblazoned, in English: “Make Russia Small Again.”