Furthermore, Mr. Trump had already mentioned to Mr. Zelensky that “the United States has been very very good to Ukraine.” There was no need to mention the withholding of funds explicitly. The leader of a country recently invaded by Russia would notice if the United States withheld funds amounting to 5 percent of its defense budget.

Indeed, while asking for a foreign country’s aid in going after a political rival is a monstrous abuse of power on its own, the memorandum is also strong evidence that Mr. Trump was offering an implicit quid pro quo. The course of the conversation makes clear the extent to which Mr. Zelensky sought Mr. Trump’s favor and assistance; in that environment, the president’s request for favors could not help being coercive.

Mr. Trump made a point of framing the conversation by saying, “we do a lot for Ukraine” and “I wouldn’t say that it’s reciprocal necessarily,” suggesting Ukraine could do more for the United States and afterward asking for favors. The implication is unmistakable: We do a lot for you, and I now expect you to do something for me.

Although there will undoubtedly be more shoes to drop, particularly when Congress receives the whistle-blower complaint that brought this scandal to light — the Senate on Tuesday unanimously approved a resolution demanding it — the memorandum is unequivocally damning. The conversation does not end with it, though. Congress’s need for other materials substantiating this apparent impeachable offense is paramount. News reporting suggests that several senior officials tried to prevent Mr. Trump from holding a meeting or call with Mr. Zelensky because they were worried that Mr. Trump would use the conversation to do precisely what he did — ask for damaging information about Mr. Biden. Congress has every right to obtain additional evidence and testimony that places the president’s conversation in appropriate context.

Mr. Trump’s pattern of betraying his country for his own personal gain stretches far beyond the favors he requested of the Ukrainian president. Toward the end of their conversation, Mr. Zelensky told Mr. Trump that the last time he traveled to the United States he “stayed at the Trump Tower.” Mr. Trump’s acceptance of Mr. Zelensky’s business may not have been an unconstitutional emolument because Mr. Zelensky was not a foreign official at the time, but the underlying problem is the same: Like others who seek to get in the president’s good graces, Mr. Zelensky patronized his businesses. The president’s profiting off the presidency and putting out his businesses as centers for cultivating influence is, and must continue to be, an important component of the impeachment inquiry.

Unfortunately, the president we see in this memorandum is not a stranger to us. It is the same man who asked a former White House counsel, Don McGahn, to fire the special counsel, Robert Mueller, and then falsely deny it later.

It is the same man whose 2016 presidential campaign was “receptive” to Russian offers of assistance, including supposed dirt about his political rival.