Washington has been engulfed over the last week by a fast-evolving story about a whistleblower complaint regarding alleged misdeeds by President Trump. Given the complexity of the reports and all the angles involved, here’s an explainer that covers the major points.

1. What did Trump allegedly “promise,” and what’s the big deal?

The big, unanswered questions here are essentially:

  1. Did Trump make some kind of “promise” to a foreign government (apparently Ukraine), as the whistleblower alleged, that would involve using official government resources for personal gain?
  2. If he didn’t make an explicit promise, how persistent were his efforts to gain foreign assistance, and was there a more implicit threat or promise?

A whistleblower from the U.S. intelligence community filed a complaint Aug. 12 that alleged some kind of wrongdoing at high levels of the U.S. government. But we haven’t seen the complaint, nor has it been shared with Congress.

Thanks to reporting from The Washington Post’s national security team, though, we now know that this whistleblower’s complaint involves Trump and alleges that he made some kind of a “promise” to a foreign leader. We then learned that the complaint involves Ukraine. By Friday afternoon, we learned that Trump had pressured Ukrainian President Volodymyr Zelensky in a July 25 call to launch an investigation involving former vice president and now presidential candidate Joe Biden and his son Hunter Biden. And on Monday, The Post’s team reported that Trump had told his administration to withhold nearly $400 million in aid to Ukraine a week before the call.

Intelligence community Inspector General Michael Atkinson reviewed the whistleblower complaint and determined it was credible. Generally, that means there is corroboration beyond just the one source. Atkinson also determined that it was a matter of “urgent concern,” which is a legal threshold that requires notifying the relevant congressional committees. In this case, that would be the intelligence committees.

2. Why isn’t the administration sharing the whistleblower complaint?

Acting director of national intelligence Joseph Maguire has refused to share the complaint, and we learned Friday that the White House Office of Legal Counsel has been involved in efforts to keep it from Congress. House Intelligence Committee Chairman Adam B. Schiff (D-Calif.) said Thursday that he understood that the Justice Department was also involved in the decision.

DNI general counsel Jason Klitenic said in a letter that the complaint “involves confidential and potentially privileged communications.” The Post reported that the White House has stopped short of asserting executive privilege over the complaint, but White House counsel Pat Cipollone has been trying to set up legal obstacles, such as claiming jurisdictional issues, to prevent Maguire from handing it over to Congress.

Trump said Tuesday that the White House would release a transcript of his call with Zelensky, but that would only address a portion of the whistleblower’s complaint.

3. How does this involve Ukraine?

The details are being filled out, and it’s still unknown how many of the dots connect. But here’s where we are:

The Trump team, and specifically his personal lawyer Rudolph W. Giuliani, has publicly telegraphed a desire to get the Ukrainian government to pursue certain investigations that might carry political benefits for Trump. These include matters involving the Biden family.

Giuliani this summer even planned a trip to Ukraine, which he readily admitted was intended to benefit Trump by pushing for particular investigations. “I’m asking them to do an investigation that they’re doing already and that other people are telling them to stop,” Giuliani told the New York Times in May. “And I’m going to give them reasons why they shouldn’t stop it because that information will be very, very helpful to my client, and may turn out to be helpful to my government.” Giuliani ended up canceling the trip amid an outcry.

Trump spoke with Zelensky, the Ukrainian president, on July 25 — 2½ weeks before the whistleblower filed the complaint — at which point he repeatedly brought up investigating the Bidens. We have now learned that Trump ordered acting White House chief of staff and Office of Management and budget director Mick Mulvaney to have the nearly $400 million withheld in mid-July. That decision was communicated to the State Department and the Defense Department on July 18, one week before Trump was to speak to Zelensky.

The proximity of those two events suggest there might be some kind of connection between them. Trump has said there was no quid pro quo, but he also suggested Monday that money could be withheld if Ukraine doesn’t root out “corruption.”

“If you don’t talk about corruption, why would you give money to a country that you think is corrupt?” Trump said. “So it’s very important that, on occasion, you speak to somebody about corruption.”

Lawmakers began raising concerns about the withheld aid in late August. Atkinson informed Congress about the whistleblower complaint on Sept. 9, and the aid was released on Sept. 11. The White House has downplayed the idea that the money was released due to the whistleblower complaint, saying it was motivated by the fiscal year, which was ending at the end of September.

4. What do we know about Trump’s phone call with Zelensky on July 25?

Logically, this would seem likely to be the conversation at the heart of the complaint. Given the parties involved in the call — Trump and Zelensky — and its temporal proximity to the complaint, that would make sense. And we’ll soon know more about exactly what the two of them said.

Trump’s repeated request of Zelensky that Ukraine investigate the Bidens would form one portion of a potential quid pro quo, but our reporting indicates Trump didn’t mention foreign aid on the call. So it’s not clear what was actually part of the “promise” the whistleblower alleges.

And Atkinson, in his closed-door testimony this week, also said the complaint involves multiple actions and no single communication, so there is a much bigger picture here.

5. Why is the Trump team so interested in Ukraine?

For a variety of perhaps unrelated reasons, Trump has eyed developments in Ukraine for potential political gain.

As The Post’s Philip Bump wrote on Friday, the first of these involved a Democratic National Committee consultant who sought information from Ukrainian officials about former Trump campaign chairman Paul Manafort, who had done work for onetime Ukrainian president Viktor Yanukovych. This was held up as a counterargument to potential Trump campaign collusion with Russia, the idea being that Democrats might have also colluded, with Ukraine.

The other big one — and apparently the more significant one when it comes to what we see today — is the situation involving the Bidens. As The Post’s Michael Kranish and David L. Stern detailed in July, Hunter Biden took a well-paying job on the board of Ukraine’s largest private gas company, Burisma Holdings, late in the Obama administration. That company had been under some scrutiny from Ukrainian Prosecutor General Viktor Shokin. Shokin was removed amid pressure from then-Vice President Biden and other Western leaders, who alleged that he wasn’t pursuing corruption cases seriously enough.

6. How substantial are the allegations against Joe and Hunter Biden?

The contention from Trump, Giuliani, et al., is that Biden was taking an action to benefit his son’s company. Shokin himself alleged to The Post “that the activities of Burisma, the involvement of his son, Hunter Biden, and the [prosecutor general’s office] investigators on his tail, are the only, I emphasize, the only motives for organizing my resignation.”

But Shokin’s contention is dubious, and it’s not clear that he had actually been scrutinizing Burisma at the time; U.S. and Ukrainian officials have said the probe had long been dormant. Shokin had also fallen out of favor with many other Western leaders, as well as with lawmakers in Ukraine, where he was the subject of a decisive vote of no confidence.

Neither of these cases involves readily apparent wrongdoing. Ukraine’s current prosecutor general told Bloomberg he had no evidence of anything illegal or corrupt by either Joe or Hunter Biden. But the Trump team seems to regard them as sleeping giants in the 2020 race — or at least issues that could be used to muddy the political waters with the leading Democratic candidate in the race (and the one who polls best against Trump).

7. Where do Joseph Maguire and the Office of the Director of National Intelligence fit into this?

Maguire’s defenders say he’s in a legitimate legal bind because the law doesn’t countenance this conflict between a president’s executive privilege and the disclosure requirements regarding a whistleblower complaint.

Regardless of whether you sympathize with him, though, he finds himself in an inauspicious position. Trump named him acting DNI a little more than a month ago under slightly controversial circumstances. After it was announced that then-DNI Daniel Coats would be resigning, Trump bypassed Coats’s No. 2, Sue Gordon, who had extensive bipartisan support, in favor of Maguire as the acting DNI. (Gordon resigned and subtly protested the decision in a brief letter.) Maguire, a retired Navy admiral, was also a somewhat unorthodox pick for the job, given his lack of experience in the U.S. intelligence community.

The overlapping timelines of Coats’s resignation, Maguire’s elevation and the whistleblower complaint are also raising eyebrows. Trump announced the exit of Coats, with whom he occasionally clashed, on July 28. That’s three days after his call with Zelensky. Trump announced Maguire’s selection Aug. 8. Four days later, the whistleblower complaint was filed.

The practical impact is that Maguire, who was Senate-confirmed but for a different job, has been thrust into a high-profile position that now involves making a very difficult legal and political call for an intelligence community in which he isn’t exactly steeped.

8. What recourse does Congress have?

Impeachment is the obvious one, and this episode seems likely to be a tipping point for many Democrats who have thus far not supported pursuing that. Most importantly, House Speaker Nancy Pelosi (D-Calif.) is now supporting an impeachment inquiry.

Short of impeachment, this an unusual situation that breaks with traditional protocol, so, as The Fix’s Amber Phillips wrote on Friday, there are limited tools at Schiff’s disposal. He acknowledged he doesn’t have a lot of options when he said Sunday on CNN that impeachment of Trump “may be the only remedy.”

He has already activated one of the remaining tools he has. Earlier this month, he subpoenaed both the whistleblower complaint and documents related to the decision to withhold it. Maguire is set to testify Thursday before an open session of Congress.

Schiff also said that he might sue over the matter and that his committee and the Democratic-controlled House could withhold funding from the DNI’s office until it relents.

Other Democrats, including House Judiciary Committee Chairman Jerrold Nadler (D-N.Y.), are considering how to use a long-dormant tool called inherent contempt that would allow Congress to fine or even jail officials who don’t comply with their subpoenas.

9. How bad is this for Trump and his presidency?

That’s the other big question right now. It’s too early to know whether it will be proved that Trump did anything wrong. Even if we see the complaint, it’s not certain that things happened exactly as the whistleblower said they did. And just because Trump pushed for investigating the Bidens and withheld money doesn’t mean there is a provable quid pro quo.

Any specific legal violations would depend on those details. Asking for foreign assistance is problematic in and of itself, but this is also the president who publicly asked for Russia to obtain Hillary Clinton’s emails in 2016 and has indicated repeatedly that he was open to foreign help. The more troubling possibility (and the one raised specifically by the “promise” allegation) is that this might involve outright government corruption — the trading of favors for personal gain. It has been suggested that such a situation could involve federal election law violations or even extortion.

Of course, even if Trump violated the law, we’re in the same position as we are with obstruction of justice and former Trump lawyer Michael Cohen’s campaign finance violation (in which Trump has been implicated but not accused of a crime). And that position is: Justice Department guidelines say a sitting president can’t be indicted; thus any remedy would be Congress’s responsibility, via potential impeachment proceedings.

The constitutional definition of an impeachable offense — “high crimes and misdemeanors” — is a subjective one that means basically whatever Congress determines it means. So the real question is whether serious wrongdoing by Trump in this case would rally public and political support in a way we haven’t yet seen for impeachment and/or removal from office.

In the background are other highly controversial things Trump has done, most notable being his potential obstruction of justice in the Russia investigation. But thus far, public support for impeachment is far short of a majority, and Republicans, who control the Senate and can easily prevent Trump’s removal from office, have shown no appetite for going down that road. Democrats have thus proceeded somewhat timidly. And with the 2020 election approaching, they might reason that the election would be the best way to decide how Trump is held accountable.

As far as that race goes, Trump finds himself in a tough spot. He has low approval ratings and trails most Democrats he potentially faces in 2020, including by double digits in the case of Biden. One more big scandal would seem to cement his underdog status, but there is plenty of time until November 2020.

10. What happens next?

First of all, we need to get more details on exactly what went down — and how explicit or implicit any official actions by Trump might have been tied to Ukraine investigating the Bidens. Again, even the transcript won’t answer the key questions. And on Sunday, the Senate voted unanimously to compel the transmission of the whistleblower complaint.

Democrats have decried the situation, but thus far Republicans with a few notable exceptions have steered clear of raising concerns. Sen. Mitt Romney (R-Utah) said, “Understanding exactly what he said would be very helpful I think to determine whether the allegations, which are quite serious, are allegations that will have consequence.” Other Republicans and Trump Cabinet secretaries have suggested Trump’s allegations concerning the Bidens merit investigation, without weighing in on whether Trump’s specific pursuit was appropriate.

Even in raising their concerns, though, some Democrats have cautioned that more needs to be known before impeachment would pass. In the op-ed from the freshman Democrats, they said, “If these allegations are true, we believe these actions represent an impeachable offense. We do not arrive at this conclusion lightly, and we call on our colleagues in Congress to consider the use of all congressional authorities available to us ...”

Trump is also scheduled to meet with Zelensky at the United Nations on Wednesday.

Amber Phillips contributed to this report.