There have been many dramatic days during the Trump presidency but perhaps none as consequential as Wednesday, which brought compelling testimony from Gordon Sondland, the U.S. ambassador to the European Union.

In clear and unequivocal language, Sondland implicated the president and other senior officials in the effort to pressure Ukrainian President Volodymyr Zelensky. He made clear that Trump was withholding military aid and a coveted Oval Office meeting until Zelensky announced investigations into Ukraine’s role in the 2016 election as well as former vice president Joe Biden and his son Hunter.

Sondland’s testimony probably accelerates the moves by House Democrats to impeach the president and send the issue to the Senate for adjudication, though at this point the odds of conviction remain long, absent a significant shift in public opinion away from the president.

Sondland became the latest in a line of witnesses who have said that any effort to pressure a foreign government to investigate a potential political rival is, at a minimum, improper and perhaps worse. That raises the question of whether Republicans, who have been unified in arguing that nothing improper took place, will now modify that position in any way to acknowledge wrongdoing by the president while arguing that it does not constitute an impeachable offense.

At a minimum, Sondland knocked down some of the defenses that Republicans have been offering during the hearings and outside the hearing room, particularly with his assertion that the terms the president was demanding of Zelensky for an Oval Office visit amounted to a quid pro quo.

He recounted a September phone call in which the president said he was not asking for such a quid pro quo, a call that Republicans have cited repeatedly as proof that Trump was not seeking such a thing from Zelensky.

But Sondland offered a bit of context to what has been said before about that statement from the president. He explained that whatever the president’s words, he did not know whether Trump was being truthful in their brief conversation, and, regardless, that he still believed there had been a quid pro quo that had held up vital military aid and a sought-after Oval Office visit for the Ukrainian president.

The president had based his defense on the rough transcript of a July 25 phone call with Zelensky, arguing that there was no explicit demand made during the conversation and describing the call as “perfect.” But Sondland described a systematic and long-running effort, directed by the president and led by his personal attorney, Rudolph W. Giuliani, to make clear to the Ukrainian leader what he was demanding of him in order to get what he was seeking from the president.

“We followed the president’s orders,” Sondland told the House Intelligence Committee.

Rather than calling this a rogue effort by Giuliani or an end run around the existing diplomatic and national security apparatus of the administration, Sondland said everything was well-known across the senior levels of the administration, in part because he personally had communicated regularly with Secretary of State Mike Pompeo and others about what was happening.

“Everybody was in the loop,” he said.

Unlike many of the others who have testified over the past week, Sondland is not part of the executive branch bureaucracy. He is a wealthy businessman who contributed $1 million to the president’s inaugural committee and ended up as the ambassador to the E.U. In that sense, he is an ally of the president and indebted to Trump for putting him where he is today.

Wednesday’s testimony was the third time he has offered evidence in the impeachment inquiry — once behind closed doors, then in a written statement in which he revised some of his original statements. On Wednesday, he said, his memory had been further refreshed by the testimony of others and a review of some of his own and other’s emails and text messages, although he said he had been denied access to many of his documents by the State Department.

He arrived for Wednesday’s hearing facing an obvious dilemma, which was to risk a charge of lying to Congress by significantly disputing testimony that had taken place after his prior statements, or openly disputing the president’s version of events and thereby risking the wrath of the president’s allies as well as many with whom he serves in the administration. He chose to take on the president.

With each new statement to the intelligence committee, Sondland has been more explicit about the president’s role. That culminated with his appearance on Wednesday. But what made his testimony as significant as it turned out to be was that he expanded the circle of those who he said were aware of what was going on. He said Pompeo, Vice President Pence, acting White House chief of staff Mick Mulvaney and former national security adviser John Bolton were all aware of what was going on.

If Sondland provided any lifeline to Republicans, it was his acknowledgment that Trump never personally told him he was demanding investigations into 2016 and the Bidens in exchange for an Oval Office meeting or the resumption of military aid. But he was explicit that he and others were told to follow the lead of Giuliani on dealing with the new government in Ukraine and, he said, that the former New York mayor was asking a quid pro quo of the Ukrainians — an Oval Office meeting in exchange for announcement of investigations.

“Mr. Giuliani was expressing the desires of the president of the United States, and we knew that these investigations were important to the president,” he said.

It was later, he said, that he concluded that military assistance to the Ukrainians was part of that quid pro quo.

Sondland took issue with aspects of the testimony by other administration officials who have been critical of the president. And some of his assertions were disputed by those he named as in the loop, including by a spokesman for Pence. But none of those at the most senior levels of the administration identified by Sondland as being aware of the pressure campaign have been heard from in sworn testimony in an open hearing room.

That includes Giuliani, who was the president’s point person on Ukraine, as well as Pompeo, who has been notably silent as career officials in his department have offered testimony that has outlined the pressure campaign that Sondland says was directed by the president.

Trump sought to distance himself from the weight of Sondland’s words, claiming he did not know the ambassador well. Nonetheless, Sondland described a friendly and jocular relationship with the president based on a shared use of salty language. “That’s how President Trump and I communicate, a lot of four-letter words,” he said.

Sondland also confirmed that he was able to call the White House on an open phone line from a restaurant in Kyiv on the day after Trump had spoken with Zelensky and speak directly to the president. While he said he could not remember the full contents of the conversation, he did not dispute other testimony that he told the president that Zelensky would do anything he asked.

Whether the House impeachment inquiry will hear from any of those in the most direct contact with the president on these matters remains an unanswered question, given their resistance to date. Sondland has significantly weakened Trump’s protestations and put the president’s Republican defenders in a far more difficult position. In that way, Wednesday was far from just another day in Washington.