William B. Taylor didn’t ask to be the acting ambassador to Ukraine. In May, Secretary of State Mike Pompeo reached out to him, recognizing Taylor’s experience both in U.S. diplomacy and with Ukraine, in particular, having served as ambassador there under George W. Bush. Taylor was cognizant of how the prior ambassador had been ousted and that Trump’s attorney Rudolph W. Giuliani was sniffing around looking for dirt, so, wary, he asked Pompeo to assure him that policy on Ukraine wouldn’t shift. Pompeo assured him it wouldn’t.

“Once I arrived in Kyiv, I discovered a weird combination of encouraging, confusing, and ultimately alarming circumstances,” Taylor said in his testimony before the House impeachment inquiry last month. “I found a confusing and unusual arrangement for making U.S. policy towards Ukraine,” he added. “There appeared to be two channels of U.S. policy-making and implementation, one regular and one highly irregular.”

He led the regular effort, through Pompeo’s State Department. The irregular effort was led by a trio of senior officials who referred to themselves as the three amigos: E.U. Ambassador Gordon Sondland, Energy Secretary Rick Perry and Ukraine special envoy Kurt Volker.

“We’ve been tasked with sort of overseeing the Ukraine-U.S. relationship between our contacts at the highest levels of the U.S. government and now the highest levels of the Ukrainian government,” Sondland told an interviewer the day after Trump’s call with Ukrainian President Volodymyr Zelensky. To House investigators, Sondland was more specific.

“President Trump was skeptical that Ukraine was serious about reforms and anti-corruption, and he directed those of us present at [a May 23] meeting to talk to Mr. Giuliani, his personal attorney, about his concerns,” Sondland said in a prepared statement. “It was apparent to all of us that the key to changing the President’s mind on Ukraine was Mr. Giuliani.”

Giuliani was a steady presence with administration officials, with Sondland testifying that Trump’s personal attorney “was always swirling around somewhere.” His requests of the “amigos” were specific, pressing Sondland and Volker, in particular, to get Ukrainian leaders to announce investigations — ostensibly because of corruption concerns — into former vice president Joe Biden and the circumstances of 2016 election interference.

What is less recognized is the world of connections that Giuliani was leveraging outside of the government. Over the past few weeks, that web of connections has become more clear, as have the ways in which Giuliani used external allies to guide his requests from the government team with whom Trump connected him.

Part of Giuiliani’s activity was revealed by an unusual packet of information he provided to the State Department earlier this year. It included summaries of interviews that Giuliani had conducted with then-current and former Ukrainian officials, including Viktor Shokin, the former general prosecutor whose firing in early 2016 is at the center of Giuliani’s allegations about Biden.

Also included in those interviews were two associates of Giuliani’s: Lev Parnas and Igor Fruman. Those names probably sound familiar: Both were indicted last month on campaign finance charges. That drew new scrutiny to their work for Giuliani. That includes a Washington Post report from this weekend indicating that the pair — at Giuliani’s direction — had pressed the outgoing president of Ukraine to launch an investigation into Biden.

When House investigators first sought information from Parnas and Fruman, their attorney, John Dowd — who had previously worked for Trump — sought to reject the requests by alleging a wide-ranging privilege involving the two. (Dowd’s relationship with Parnas later ended.)

“Parnas and Fruman assisted Mr. Giuliani in connection with his representation of President Trump,” Dowd claimed. “Mr. Parnas and Mr. Fruman have also been represented by Mr. Giuliani in connection with their personal and business affairs. They also assisted Joseph diGenova and Victoria Toensing in their law practice.”

That connection with diGenova and Toensing is interesting in its own right. The pair have two other clients of interest to Giuliani’s work in Ukraine.

One is John Solomon, a journalist who first reported a number of allegations against Biden or other targets of Giuliani’s, often to see them later retracted or debunked.

The other client is Dmytro Firtash, a Ukrainian tycoon who has been accused of bribery. Parnas served as a translator for Firtash and recommended he hire diGenova and Toensing. Firtash was reportedly persuaded to hire the pair in part because their son works for the Department of Justice, a potentially useful connection for a guy facing possible criminal charges.

Bloomberg News reported last month that Firtash more directly sought to influence the government, building goodwill with Giuliani in part by eliciting derogatory testimony from Shokin targeting Biden. According to Bloomberg News, people working for Firtash got a sworn affidavit from Shokin — which was then published by Solomon in late September.

Giuliani embraced that affidavit, including referring to it during a Fox News interview as “the affidavit I put out.” That wasn’t his first link to Solomon. Included in the packet Giuliani provided to the State Department was an email from Solomon to Parnas, Toensing and diGenova with an early draft of a Ukraine-related email. It also included a number of Solomon articles focused on bolstering allegations about Ukraine.

That packet of information got to the State Department in March. In April, Zelensky won the presidency in Ukraine. Shortly after he was inaugurated, Trump tasked the amigos with working with Giuliani on addressing “corruption” in the country.

Five days later, Pompeo asked Taylor to step in to lead the embassy in Ukraine. He soon learned about the universe of activity that was hoping to push things in a very specific direction.

Correction: Dowd no longer represents Parnas. An earlier version of this article indicated that he'd ended his relationship with Fruman.