President Trump began the day at the Pentagon, inspecting a military parade with soldiers marching in full dress uniform and shouldering rifles with gleaming bayonets. The occasion for this pomp and circumstance, which the president so enjoys, was a welcoming ceremony for new Defense Secretary Mark Esper, who had just won Senate confirmation. But while the day marked a bipartisan triumph for Trump, history may mark it as the moment he gave Democrats a final rationale for his impeachment.

Either while driving in a motorcade or sitting in the Oval Office on July 25, Trump placed a call to Ukraine President Volodymyr Zelensky. The Wall Street Journal later reported that Trump asked the foreign leader, up to eight times, to investigate the Ukrainian business dealings of Hunter Biden, son of former Vice President Joe Biden.

Trump, it was later reported, had placed a hold on $391 million in military aid to Ukraine a week before the phone call, which was the impetus for a whistleblower complaint. Alleging a quid pro quo, a growing number of Democrats are demanding the commencement of impeachment proceedings.

“The actions taken to date by the president have seriously violated the Constitution,” House Speaker Nancy Pelosi told reporters Tuesday evening after a day of deliberating with her caucus. The president “must be held accountable. No one is above the law.”

A formal impeachment inquiry is now official, and while it remains to be seen whether Democrats will actually charge the president with high crimes and misdemeanors, the move is the most serious step Democrats have taken toward ousting Trump early from the Oval Office.  

Administration officials insist that the president was not withholding assistance to a strategic U.S. ally for his own political benefit. A senior administration aide told RealClearPolitics that the president requested the hold so that Esper and then-national Security Adviser John Bolton could “run a policy process” on the account.

The review process was necessary, according to the aide, to ensure the funds would not be squandered and that other European allies were shouldering their fair share of the defense burden.

“The president has consistently made it clear that any foreign aid spent overseas must not only run through a good-government process, but also protect U.S. interests abroad,” the aide told RCP. “That good-government process was run by the president’s policy team on this account to ensure that those goals were met.”

The review began in June and was concluded in September when the new funds were finally released. The delay had nothing to do, the officials maintain, with questions about Hunter Biden, who was hired in 2014 by the Ukrainian gas company Burisma Holdings despite lacking any background in European affairs or experience in the energy industry.

Trump’s attorney, Rudy Giuliani, has accused former Vice President Biden of pressuring Ukraine’s government to fire a prosecutor who was investigating Burisma Holdings for corruption.

“When Biden got the prosecutor fired, the new prosecutor who Biden approved -- you don’t get to approve a prosecutor in a foreign country unless something fishy is going on -- the new prosecutor dropped the case," Giuliani said on “Fox News Sunday.”

Before addressing the U.N. General Assembly Tuesday, even while House Democrats huddled to determine their next course of action, Trump again insisted that the delay was aboveboard.

“I want other countries to put up money. I think it's unfair that we put up the money,” he said. “Then people called me; they said, 'Oh, let it go.' And I let it go. We paid the money. The money was paid. But very importantly, Germany, France, other countries should put up money.” Trump added that making sure NATO allies pay their fair share of defense needs has “been my complaint from the beginning.”

Questioning how much the U.S. should pay in foreign aid and for overseas military spending has been a political and policy staple of the president since before his election. It’s a position that has put him at odds with some Republicans. But it is now up to Democrats to judge for themselves if Trump was just continuing his “America First” foreign policy – or doing something much more nefarious regarding Biden, the Democrats’ 2020 front-runner.

The president promised on Twitter to release a declassified and unredacted transcript of the call on Wednesday. Meanwhile, key Senate Democrats expressed skepticism that the funding was delayed, in part, to allow a review by Bolton and Esper.

“The administration at any level has never shared with the committee -- and we are the committee of jurisdiction -- anything about a policy review as it relates to Ukraine,” New Jersey Sen. Bob Menendez told RCP. “On the contrary, we asked the State Department specifically whether they had any issues with the monies going to Ukraine and their answer was no, and they had not raised any policy issues” with the Office of Management and Budget.

“So, I don’t know what the review was,” the ranking member of the Senate Foreign Relations Committee continued. “This is what we would call the ultimate alternative facts.”

Others, like Sen. Ben Cardin, were more guarded. “We knew that there were some changes because they were fooling around with the aid,” the Maryland Democrat told RCP. “But we were not aware that there was a formal policy review.”

This kind of confusion was not limited to the left side of the aisle. The Republican chairman of the Foreign Relations Committee, Idaho Sen. Jim Risch, told RCP he was not aware of the Bolton-Esper policy review. Majority Leader Mitch McConnell was similarly unaware, telling reporters he had “no idea what precipitated the delay.”

A senior administration official disputed that contention. The aide told RCP that the White House did not ask permission or notify any committee but insisted that lawmakers on Capitol Hill knew of the reason for the delayed funds.

Neither the State Department, the National Security Council, nor the Pentagon replied to RCP requests for comment.

Ultimately, review-related holds might not count for much in staving off Democrats. House Speaker Nancy Pelosi is  believed to be working on a formal impeachment inquiry of the president, and already Senate Minority Leader Chuck Schumer has said that a transcript of the phone call will not be enough to satisfy him. He has not tipped his hand on impeachment but told reporters Tuesday that he wants to see the original whistleblower complaint.

The question of impeachment now places Ukraine in the middle of a political firefight in far-away Washington, D.C., and as the 2020 election looms. For his part, the president promises not to turn his back on the Eastern European country combating the Russian aggression.

“President Obama used to send pillows and sheets,” he told reporters. “I sent anti-tank weapons and a lot of things to Ukraine.” In response to the Democratic chorus calling for impeachment, he asked. “How can you do this, and you haven’t even seen the phone call?”