A tumultuous week in Washington has set the stage for an intense new congressional investigation into President Trump — and what could prove to be a historic clash between the White House and Congress.
The outlines are now clear about conduct that no one, including Trump, disputes: The president asked his Ukrainian counterpart to investigate the family of Vice President Joe Biden, a potential political rival in the 2020 presidential election.
If Trump was sanguine about confirming that story — which the White House did with the extraordinary release on Wednesday of its own records about the conversation — House Democrats want the answers to more questions before they decide how much further to travel down a road they've said could lead to impeachment.
Some of these questions were raised by the release on Thursday of the previously secret complaint by an intelligence community whistleblower that sparked the Ukraine affair.
In that document, the complainant suggests that intermediaries told Ukrainian officials beforehand that a phone call or a meeting between President Volodymyr Zelenskiy and Trump would depend on "whether Zelenskiy showed willingness to 'play ball' " with Trump.
"I do not know who delivered this message to the Ukrainian leadership, or when," the whistleblower added.
House Democrats want to learn the identities of those people and where their communications fit into the story.
Although Trump and his supporters argue that the White House's account of Trump's call with Ukraine's president doesn't record a "quid pro quo," the full picture has not been made clear.
Did an aide or a diplomat tell Kyiv beforehand that U.S. military assistance to Ukraine was being suspended — as it was in the summer — as the prelude for a phone call in which Trump could expect Zelenskiy to ask for it to resume?
Zelenskiy did just that, according to the White House's account.
When he told Trump that Ukraine was "ready to continue to cooperate" to buy more weapons from the U.S., that prompted Trump to ask him for a "favor" that he hoped might lead to information about the Biden family.
House intelligence committee Chairman Adam Schiff, D-Calif., told reporters on Thursday after a hearing about the whistleblower complaint that he wants to learn whom the intelligence community's inspector general has talked with about the Ukraine affair and then begin seeking witnesses of his own to fill out the story.
Inside the family
The complaint also describes a practice within the White House of compartmentalizing accounts of potentially politically sensitive Trump calls in a separate close-hold system that limits access even within the administration.
The system includes records of other presidential transcripts too, the complaint says.
People who've served in the White House in past administrations have said that's not a conventional practice.
When did it begin and why? Does the secret system described in the complaint actually contain records about other presidential phone calls with foreign leaders that resemble Trump's talk with Zelenskiy? What did Trump say?
Trump has vowed to be transparent about the Ukraine affair. He volunteered on Wednesday to release records about two other phone calls with Ukrainian leaders involving himself and Vice President Pence.
Trump also has suggested that he might not object to his attorney, Rudy Giuliani, speaking with congressional committees about the central role he has played in the outreach to Ukraine.
But if past is prologue, the White House may not be eager to cooperate much more with what Trump and his supporters call Democrats' new "witch hunt."
The administration has not given Congress documents or access to witnesses in response to many of its earlier requests involving the Russia investigation, Trump's business dealings and more.
The president's supporters have dismissed the Ukraine flap as another "information warfare operation" against the president.
Meanwhile, some of the disputes between the House and the administration are still playing out in court after committees filed suit for the relevant materials.
What isn't clear is whether the theoretically greater stakes of the Ukraine matter — which House Speaker Nancy Pelosi and Democrats have made the focus of what they say is an impeachment inquiry — may prompt Trump to change his tune.
The White House already has invoked executive privilege — the doctrine that permits an administration to shield some of its internal workings from public view — in keeping some witnesses and materials from Congress.
The investigation that Schiff and his colleagues now want to pursue involves the internal workings of the White House, discussions of the National Security Council and other aides, diplomats and others all squarely within the executive branch.
If Giuliani, who has been working for Trump but not the government, isn't covered by executive privilege, many of the other people involved may be.
Executive privilege already has been the subject of internal debates involving the whistleblower case, acting Director of National Intelligence Joseph Maguire told Schiff's committee on Thursday.
Are Pelosi and Schiff about to drive into a wall they'll be unable to breach? Or will the putative threat of impeachment prompt Trump to open the gates?
The red wall
Trump may remain confident that in the event of actual impeachment proceedings — which would involve the equivalent of an indictment in the House and then lead to his trial in the Senate — he'd continue to enjoy the support of enough Republicans to retain the presidency.
That has been the assumption by Republicans thus far, and as Washingtonians headed to work on Friday morning, the red wall in the Senate still appeared robust.
At times, the president and his supporters have appeared to want to dare Democrats to go ahead with impeachment with the knowledge that they would lose, betting that the fallout actually would wind up weakening Pelosi and her members and strengthening Trump and Republicans.
Before this week, Pelosi seemed to read these politics in the same way and sought to rein in the most aggressive Democrats in the chamber. Then the accounts of Trump's conduct broke the dam for so many of her members that the speaker joined them on Tuesday under the aegis of the I-word.
But Pelosi also hasn't spelled out what, precisely, she, Schiff and her other top lieutenants actually may do differently, nor has she made clear how far Democrats are prepared to go.
That has put the speaker in an uncertain new standoff with the president, and the next phase in this melodrama may depend on who's the first one to blink.