Up until a few weeks ago, Ukraine had always been something of a backwater in U.S. politics and diplomacy — in a good way. The megadonors and social peacocks who preside over U.S. embassies elsewhere in Europe were nowhere to be found in Kiev. Instead, U.S. policy was served by a string of top-notch professional ambassadors.

That policy, too, was mostly consistent and uncontroversial. For three decades Republican and Democratic administrations steadily pursued the same goals: helping Ukraine ward off aggression from Russia and strengthen its democracy. Both of those objectives involve fighting corruption, which is Ukraine’s biggest political problem and one of the main means of Russian influence.

Needless to say, that era is over. In a matter of months, President Trump and his personal lawyer, Rudolph W. Giuliani, have twisted U.S. policy in Ukraine to their personal ends, touching off turmoil inside the White House and State Department and weakening — perhaps critically — a bilateral relationship that is crucial to containing Russian aggression in Europe.

The story of Trump’s strongarming of Ukrainian President Volodymyr Zelensky is first and foremost one of Trump’s abuse of his presidential power in pursuit of personal political gain. But it is also an epic example of how Trump has destroyed U.S. diplomacy in places around the world where, for years, it had worked smoothly and relatively effectively despite the growing partisan polarization in Washington.

As one of the relatively few U.S. journalists who has followed Ukraine closely over the years, I find that the saddest part of this story has been watching a once-cohesive community of U.S. diplomatic pros on Ukraine be crushed as it tried to contain and manage the hurricane-like intervention of Giuliani and Trump. The whistleblower’s complaint offers a partial picture of this unraveling, and I have heard more in several conversations with longtime sources.

Though Trump never had a positive view of Ukraine, the trouble really started with Giuliani, who has a record of working for and with the very Ukrainian actors that U.S. policy has aimed to marginalize: shady business executives and corrupt politicians with ties to Russia, organized crime or both.

Beginning early this year Giuliani began gathering what the Russians call kompromat — dirt — on Trump’s present and potentially future political opponents. His prime sources were a pair of state prosecutors who were universally regarded by reform advocates in and outside Ukraine as corrupt. The two fed Giuliani concocted stories about their adversaries: One prosecutor targeted Joe Biden, who in 2016 had joined an international campaign to force him from office, while the other slimed the U.S. ambassador to Ukraine, who had criticized his inaction on major corruption cases.

When Giuliani began spreading his poison to Trump and conservative media, U.S. officials were, as the whistleblower put it “deeply concerned.” At first, some were inclined to dismiss the former New York mayor as a sideshow. But by late May, they realized he had done real damage. When members of the U.S. delegation to Zelensky’s May 20 inauguration reported back to Trump at the White House and expressed enthusiasm about the new president, Trump launched into a tirade about Ukrainian corruption and a supposed Ukraine-based conspiracy to prevent his election. He then refused to schedule a meeting with Zelensky.

For the Ukraine pros, this was particularly dismaying because Zelensky, a political newcomer who had won a landslide victory on an anti-corruption platform, seemed more serious than any of his predecessors about tackling the country’s oligarchs and compromised judicial system. One of his first steps was to ask parliament to sack Yuriy Lutsenko, one of the prosecutors feeding Giuliani dirt.

What to do? Some thought it best to simply keep Trump away from Ukraine. But then the State Department came up with a classic State Department solution: Organize talks. If Giuliani could be peeled away from Lutsenko, officials reasoned, and Trump could hear for himself how committed Zelensky was to fighting corruption, they might shift their views. Kurt Volker, a veteran diplomat who was State’s special envoy for Ukraine, set up conversations between Giuliani and a close aide to Zelensky.

Volker also pushed for a phone call between Trump and Zelensky. The idea was that Zelensky would talk about his plan to “drain the swamp” in Kiev and Trump would then offer him the visit to the White House that the Ukrainian badly wanted.

The problem is that the pros misread Trump. He had no genuine interest in Ukrainian corruption. He simply wanted to squeeze the Ukrainians for the dirt on Biden and the Democrats that Giuliani said they had.

The result was the disastrous July 25 phone call, which led to the whistleblower’s complaint and may yet lead to Trump’s impeachment. Volker resigned Friday. The collateral damage will be the U.S.-Ukraine relationship — and the pros who found themselves steamrolled by the counterparts in Washington of Kiev’s corrupt thugs.

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