KIEV, Ukraine — Ukrainian leaders are trapped in the middle of a very Washington firefight, facing mounting pressure from President Trump and his allies to investigate the son of political rival Joe Biden, and are searching for a way to escape.

They could give in to Trump’s demand to open an inquiry into the Ukrainian business dealings of Hunter Biden and risk the anger of Democrats and others for engaging in what those interests would see as interference in the 2020 elections. Or the Ukrainians could defy Trump and face the wrath of a president who had frozen $250 million of crucial military assistance for mysterious reasons before releasing it earlier this month.

Either way, they risk cracking the bipartisan consensus that has firmly supported Ukraine against Russia since 2014, when the Kremlin annexed Ukraine’s Crimea region and stoked war in Ukraine’s east. If Ukraine becomes associated with one U.S. political party or the other, it could jeopardize ties with its most important security backer.

“It’s a diplomatic disaster for our relations with the United States,” said Alyona Getmanchuk, the director of the New Europe Center, a Kiev-based foreign policy think tank. “I don’t know what could be the way out of this story.”

The predicament could come to a head Wednesday, when Trump is to sit down, for the first time, with Ukrainian President Volodymyr Zelensky on the sidelines of the United Nations General Assembly in New York.

Zelensky has sought the meeting for months, seeing it as a way to demonstrate U.S. support for a country that is still fighting a war in its east and enduring Russia’s annexation of Crimea. Trump has been reluctant, and he pressed Zelensky about Biden in a July phone conversation that is the subject of an extraordinary intelligence community whistleblower complaint.

Diplomats, politicians and analysts inside and outside Ukraine said Saturday that Ukraine was in a precarious position.

“Really couldn’t get worse” for Kiev, said a senior European diplomat, speaking on the condition of anonymity to avoid aggravating the situation.

“I’m afraid to do even more harm to Ukraine,” said a normally gregarious former policymaker, turning down a request for comment.

Zelensky – who until recently was a comedian with no political experience – will have to tread carefully. A misstep could further inflame the situation in Washington, costing Ukraine its ties either to Republican or Democratic lawmakers.

Since Trump has embraced Russian President Vladimir Putin and questioned both NATO and the reasons to support Ukraine, the bipartisan backing for the country in Congress has come to represent the main U.S. security guarantee for Kiev. If that were eroded, Ukraine could be in an especially dangerous position.

“Our vital interest is to ensure and to protect and to strengthen the bipartisan support for Ukraine,” said Danylo Lubkivsky, a former Ukrainian deputy foreign minister. “This is not all about Ukraine. Don’t impose some domestic issues, problems on Ukraine, while Ukraine fights against Russia’s aggression and struggles for its independence and freedom.”

Zelensky is also talking about meeting with Putin as well as with the leaders of France and Germany in the coming weeks to try to hammer out a settlement to the conflict that is in its fifth year. That makes the uproar in Washington especially unsettling, because it weakens Ukraine’s negotiating position.

Zelensky has been more open to Russia than his predecessor, negotiating a major prisoner swap with the Kremlin in addition to suggesting discussions with Putin.

“The ultimate beneficiary of all this story is Russia,” said Daria Kaleniuk, the executive director of the Anti-Corruption Action Center, a clean-governance organization in Kiev.

Already, some Ukrainians worry that Zelensky may have offered too much to Trump’s team.

“Just stay away from it. It is not our story. There is nothing to gain, there is lots to lose,” said Victoria Voytsitska, a former Ukrainian lawmaker who was swept into office in 2014 in a wave of Western-oriented activists who entered politics after the political upheavals that year.

Using an investigation “as a tool to say we’re reopening this to provide a benefit, leverage to a particular candidate, would be a mistake,” she said.

Ukrainian policymakers and analysts worry that their leader is walking into an ambush by meeting Trump on Wednesday. They fear it could set back efforts to improve the rule of law made since the 2014 revolution, which overthrew a deeply corrupt leader.

One irony is that U.S. resources have been poured into Ukraine since its 1991 independence from the Soviet Union to try to foster an independent judiciary, one that could stand up political pressure – the exact sort of pressure Trump is now applying, Getmanchuk said.

Capitulating “would be a disrespect to all the Americans who gave funds and investment from U.S. taxpayers for 28 years for reforms,” she said.

Days after the July phone conversation between Trump and Zelensky, Trump’s personal lawyer Rudy Giuliani followed up with an in-person meeting with Andriy Yermak, a top Zelensky aide, in Madrid, Giuliani said. Giuliani said that he met with Yermak to suggest two matters for investigation and that Yermak indicated the Ukrainians were open to pursuing the investigations. Yermak did not respond to a request for comment.

The first matter concerned allegations that Ukraine’s government colluded with Democrats in 2016 to try to derail Trump’s presidential bid.

During the 2016 presidential campaign, the release of a ledger documenting millions of dollars of off-books payments from the former Ukrainian government to Paul Manafort helped lead to Manafort’s ouster as Trump’s campaign chairman. Manafort had been a consultant to Ukrainian President Viktor Yanukovych, the Russia-friendly leader who was forced to resign in 2014.

Giuliani said that the release of that information was part of a coordinated campaign by the Ukrainian government to help Democrats. He offered no evidence.

Serhiy Leshchenko, the Ukrainian lawmaker who revealed the ledger, says he released the information to try to fight corruption in Ukraine, not intervene in U.S. politics.

The second matter raised by Giuliani involved a probe of the Ukrainian gas tycoon who put Hunter Biden on the board of his company Burisma.

In 2016, then-Vice President Joe Biden demanded the ouster of Ukraine’s top law enforcement official, Prosecutor General Viktor Shokin.

Trump and Giuliani have accused the elder Biden of pushing for Shokin’s dismissal to protect Hunter Biden from an investigation into Burisma.

But it is unclear how seriously Shokin was pursuing Burisma at the time he was forced out. Diplomats said at the time that Shokin’s ouster was tied to Western worries about corruption in Ukraine’s justice system. Washington’s concerns were widely shared by Ukraine’s European partners, and they embraced Shokin’s departure.

“The Fake News Media and their partner, the Democrat Party, want to stay as far away as possible from the Joe Biden demand that the Ukrainian Government fire a prosecutor who was investigating his son,” Trump wrote Saturday on Twitter.

Biden said Saturday that he had never spoken with his son about his business in Ukraine and accused Trump of “doing this because he knows I will beat him like a drum.”

Comments are not available on this story.