Democratic committee chairmen released a stunning cache of text messages late Thursday night detailing exchanges among senior U.S. diplomats as they went to great lengths to play along with President Donald Trump’s campaign to pressure a foreign government to launch an investigation into his political rival.

The texts laid bare, with great specificity, a coordinated effort among State Department officials and Trump attorney Rudy Giuliani to compel the new Ukrainian government of Volodymyr Zelensky to publicly commit to investigating a firm tied to former Vice President Joe Biden’s son, thereby making foreign aid contingent on the Ukrainians helping Trump’s re-election efforts.

By September, that effort so alarmed the recently appointed chargé d’affairs at the U.S. Embassy in Kyiv, Bill Taylor, that he called it “crazy” and spiraling toward a “nightmare scenario.” Another Trump appointee, U.S. Ambassador to the European Union Gordon Sondland, insisted Taylor was “incorrect” about Trump dangling a “quid pro quo” before Zelensky—the same quid pro quo that Sondland and his colleagues, from Trump on down, had spent months orchestrating.

“As I said on the phone, I think it’s crazy to withhold security assistance for help with a political campaign,” Taylor said in a message dated Sept. 9, 2019, referring to the White House decision to mysteriously withhold nearly $400 million in military assistance that Ukraine needs to fight back against Russian forces waging war against the country in the east.

The Washington Post reported that Trump ordered the funds withheld nearly a week before his July 25 phone call with Zelensky, the contents of which were presented in a memo released last week by the White House.

With the Ukrainians alarmed over having their military aid from Washington suddenly frozen, Taylor grew urgent. “The message to the Ukrainians (and Russians) we send with the decision on security assistance is key,” he texted Sondland. “With the hold, we have already shaken their faith in us. Hence my nightmare scenario.”

The letter, which included the text messages, was written jointly by the chairmen of the House committees on intelligence, Oversight and Reform, and Foreign Affairs, and was circulated publicly following a marathon deposition on Capitol Hill from one of the pressure campaign’s key participants, the Ukraine envoy Kurt Volker, whom Secretary of State Mike Pompeo pushed into resigning last week.

“These text messages reflect serious concerns raised by a State Department official about the detrimental effects of withholding critical military assistance from Ukraine, and the importance of setting up a meeting between President Trump and the Ukrainian president without further delay,” the chairmen wrote. “He also directly expressed concerns that this critical military assistance and the meeting between the two presidents were being withheld in order to place additional pressure on Ukraine to deliver on the president’s demand for Ukraine to launch politically motivated investigations.”

Giuliani, in comments to The Daily Beast late Thursday, said “military aid never came up in the conversations I had with [Gordon] Sondland or Kurt” Volker, adding “I feel vindicated when I look at the texts. It certainly shows I was being directed by them [in the State Department]. They brought me into it. They were calling the shots. There were a lot of things they were doing that I didn’t know about. It shows they weren’t upset with anything I was doing. Nor do I find anything they did irregular... Seems to me they were doing their jobs effectively. Nothing at all sinister about it.”

While the impeachment inquiry is being spearheaded by the intelligence committee, led by Rep. Adam Schiff (D-CA), who has become a main target of Trump and his allies, the House Oversight and Government Reform and Foreign Affairs committees led by Maryland Rep. Elijah Cummings and New York Rep. Eliot Engel, respectively, also have ongoing investigations as a part of an impeachment inquiry.

Less than a week before Trump’s infamous July 25 phone call with Zelensky—in which the president responded to Zelensky’s interest in buying additional anti-tank missiles by asking Zelensky for “a favor”—Volker connected Zelensky adviser Andriy Yermak with Giuliani. He texted with Sondland afterward that it would be “most impt” that Zelensky say on the upcoming call between the two presidents “that he will help investigation.”

Taylor began to grow concerned. He texted Sondland that the Ukrainians did not want to be seen as “an instrument in Washington domestic, reelection politics.” Sondland, whom the committees seek to depose over Pompeo’s objections, replied that “we need to get the conversation started and the relationship built, regardless of the pretext.”

The texts also indicate that the senior National Security Council official responsible for Russia and related affairs, Tim Morrison, was aware of the effort in some form. Sondland texted three days before the Trump-Zelensky call—something Giuliani “was advocating,” Volker texted on July 22—that he spoke with Morrison.

On July 25, shortly before the call occurred, Volker said he had heard “from White House” that they might work out an in-person meeting between Trump and Zelensky “assuming President Z convinces trump he will investigate/’get to the bottom of what happened’ in 2016.” On the call, Trump pressed Zelensky for help discrediting Special Counsel Robert Mueller’s already-completed investigation into Russian interference in the election, which pointedly did not exonerate Trump.

Zelensky appeared to think his meeting with Trump was on. Sondland noted on Aug. 9, “I think potus really wants the deliverable”: a public commitment to investigate Trump’s enemies. Sondland proposed getting a draft statement from the Ukrainians. Yermak told Volker that Zelensky wanted a commitment for a bilateral meeting before the Ukrainians made their announcement. The Americans reached out to Giuliani about the statement.

By Aug. 13, Volker and Sondland texted about the proposed Ukrainian statement. It was to declaim “interference in the political processes of the United States” while roping Ukraine into them, through promising a “transparent and unbiased investigation” that specifically mentioned Burisma, the natural-gas concern on whose board Biden’s son, Hunter, sat for no reason besides his name, “and the 2016 elections.” Four days later, Sondland asked, “Do we still want Ze to give us an unequivocal draft with 2016 and Burisma?” Volker replied: “That’s the clear message so far…”

But neither the statement nor the meeting happened. Yermak panicked after reading a Politico story about Trump holding up the military aid for Ukraine. Then Trump canceled the plans for the two leaders to meet.

By Sept. 1, Taylor grew panicked himself. Incredulous, the charge d’affairs texted Sondland: “Are we now saying that security assistance and WH meeting are conditioned on investigations?” Whatever Sondland replied was not contained in the texts. “Call me,” he told Taylor instead. (On Friday morning, Ukraine’s top prosecutor announced a review of the closure of past investigations of Burisma.)

That call is likely to be of substantial interest to the House Democratic impeachment inquiry. The three chairmen told their colleagues late Thursday in their letter, “This is not normal or acceptable. It is unethical, unpatriotic and wrong.”