Rep. Devin Nunes (R-Calif.) is under fire from Democrats who say the House intelligence committee chair should recuse himself from the committee's investigation into Russia, because he's too close to President Trump. Can Nunes retain his credibility as the investigation plays out? (Peter Stevenson/The Washington Post)

As in any good spy story, the twists and turns in the real-life spy drama gripping Washington right now can be hard to follow.

There are three questions that the House and Senate intelligence committees and the FBI are trying to answer with their own investigations:

1. What is the extent of Russia's meddling in the U.S. election to help Trump win, as intelligence agencies have concluded, and what can be done to prevent it from happening again?

2. Did Trump campaign associates collude with Russia on said meddling?

3. Were Trump campaign associates caught up in unrelated spying of foreign nationals, and, if so, who leaked that fact to the public? (The identity of any U.S. national caught up in surveillance is kept secret from all but a handful of people.)

But in the eyes of national security experts, Democrats and even some Republicans, House Intelligence Committee Chairman Devin Nunes (R-Calif.) has jeopardized the impartiality of his committee's investigation into the above questions by appearing to work with the White House to uncover information.

Now, Democrats are publicly calling for Nunes to step down from the House investigation.

Here's a timeline of everything you need to know about what led to this point:

November-December: Nunes serves as an adviser on the Trump transition team.

Jan. 25: The House Intelligence Committee announces it is investigating possible ties between Russia and President Trump's election campaign. In a joint statement, Nunes and the top Democrat on the committee, Rep. Adam B. Schiff (Calif.), say they'll be looking at “any intelligence regarding links between Russia and individuals associated with political campaigns.”

“This issue is not about party, but about country,” they say. “The committee will continue to follow the facts wherever they may lead.”

March 4, 6:35 a.m.: President Trump tweets a shocking allegation:

The president and his team offer no evidence that his predecessor had wiretapped then-candidate Trump. But they demand that Congress investigate their claims.

The week of March 6-10: The president's allies struggle to defend his accusation. “I don't think we should attack the president for tweeting,” Nunes tells reporters.

Rep. Devin Nunes (R-Calif), the chairman of the House Intelligence Committee, said on March 7 that reporters shouldn't take President Trump's tweets "literally" because he's a "neophyte to politics." (Reuters)

The week of March 13-17: Still struggling to provide evidence of the wiretapping, Trump's allies start walking back his accusation. “If you look at the president's tweet, he said very clearly, quote, 'wiretapping' — in quotes,” White House press secretary Sean Spicer says at a March 13 news conference.

March 15: Trump appears to lose one of his closest allies on Capitol Hill. “I don't think there was an actual tap of Trump Tower,” Nunes tells reporters during his and Schiff's near-daily briefings on Capitol Hill, adding, “Clearly the president was wrong.”

House Intelligence Committee Chair Devin Nunes (R-Calif.) and Ranking Democrat Adam Schiff (Calif.) expressed doubt, March 15, about President Trump's claim of a 2016 wire tap at Trump Tower. (Reuters)

But Nunes does give the president this: “I think it's very possible” that Trump and his associates' names were swept up in unrelated wiretapping. (In spy language: incidental collection.)

March 16: With Trump's allies on Capitol Hill slipping away, Spicer scrambles to justify the president's insistence he was wiretapped. In a news briefing, Spicer points to an unsubstantiated claim made by a now-former Fox News contributor that President Barack Obama worked under the table with the British spy agency to tap Trump's phones.

White House press secretary Sean Spicer on March 16 said President Trump "stands by" allegations he made that President Barack Obama ordered a wiretap on him in 2016. Trump has provided no evidence for the claims. (Reuters)

March 16-March 17: Britain's national security agency derides the claim that Obama worked with it to wiretap Trump as “utterly ridiculous.” There are conflicting reports from the White House about whether Trump apologized to Britain for making the allegation.

In an unrelated news conference Friday with German Chancellor Angela Merkel, Trump backs away from ownership of the assertion by saying the White House was just reading off a news report.

At the White House briefing, March 16, press secretary Sean Spicer quoted from a Fox News report alleging former president Barack Obama had access to intelligence on President Trump through the GCHQ. In response, the British intelligence agency denied this. (Reuters)

Monday, March 20: The House Intelligence Committee holds a rare public hearing on Russian meddling in the U.S. election, featuring FBI Director James B. Comey and National Security Agency Director Mike Rogers.

FBI Director James B. Comey and NSA Director Mike Rogers appear in front of the House Permanent Select Committee on Intelligence on March 20. (Matt McClain/The Washington Post)

In the hearing, Comey acknowledges for the first time that, yes, the FBI is investigating Russian meddling and any potential Trump associate connections. Democrats lay out their case for why they're pretty sure Trump's campaign did collude with Russia, while Republicans reiterate the White House's talking points on wiretapping.

“We know there was not a physical wiretap of Trump Tower,” Nunes says. “However, it’s still possible that other surveillance activities were used against President Trump and his associates.”

Tuesday, March 21: Nunes makes a secret visit to the White House. We now know that Nunes was on White House grounds (not in the White House proper) looking at classified information to, in his words, “confirm what I already knew” about wiretapping.

Wednesday, March 22: Nunes goes to the White House, cameras in tow, to brief the president on some big news: He has evidence that Trump campaign officials were likely caught up in spying.

He holds a hastily gathered news conference outside the West Wing of the White House, where he refuses to share his source or reveal the actual information he has. “What I’ve read seems to me to be some level of surveillance activity — perhaps legal, but I don’t know that it’s right,” Nunes tells reporters. “I don’t know that the American people would be comfortable with what I’ve read.”


Nunes speaks with reporters at the White House on March 22. (Jabin Botsford/The Washington Post)

But he repeats that Obama never authorized a wiretap specifically on Trump.

In a response to a reporter's question on whether he feels vindicated by what Nunes found, Trump says this:

Democrats are caught off guard by this news, which Nunes failed to share with the committee. They don't call on him to step down, but Rep. Elijah E. Cummings (Md.), the top Democrat on the House Oversight and Government Reform Committee, says Nunes should be investigated for potentially providing information to someone under investigation.

At a news briefing Friday, Spicer is at a loss to explain why Nunes briefed the president on information that it appeared Trump already had. “I did not sit in on that briefing,” Spicer says. “I'm not — it just doesn't — so I don't know why he would brief the speaker and then come down here to brief us on something that we would have briefed him on. It doesn't really seem to make a ton of sense. So I'm not aware of it, but it doesn't really pass the smell test.”

Thursday, March 23: Democrats on the committee say Nunes apologized to them for bypassing them and going straight to the White House.

Monday morning, March 27: News organizations report Nunes's earlier, previously unknown, White House trip.

Monday afternoon: Ethics and security experts are flummoxed as to why Nunes would need to go to the White House at all, let alone twice. They don't understand why he would:

(a) brief the president on documents apparently already in the White House's possession.

(b) work with the executive branch to obtain documents when he has subpoena power to see pretty much whatever he wants.

(c) brief the president — whose associates' ties to Russia might be the subject of the Intelligence Committee's investigation — before briefing his own committee members

Also Monday afternoon: Senate Minority Leader Charles E. Schumer, one of the highest-ranking Democrats in Washington, goes to the Senate floor and calls on House Speaker Paul D. Ryan (R-Wis.) to take Nunes off the investigation. Ryan replies via a spokeswoman that he has “full confidence” in Nunes to conduct an impartial investigation.

Monday evening: Schiff calls on his colleague to step down. 

Monday evening: A defiant Nunes says in multiple TV interviews that he needed a secure location to view these classified documents, which is why he went to the White House. “I'm sure that the Democrats do want me to quit, because they know that I'm quite effective at getting to the bottom of things,” he tells Fox News's Bill O'Reilly.

Democrats and security experts point out that Nunes, who is one of eight members of Congress with access to the nation's deepest spy secrets, has his own secure location on Capitol Hill to view such documents.

Tuesday morning, March 28: “It just doesn't make sense,” Schiff tells NPR, citing the above.

Some Republicans in Congress are also perplexed by Nunes's behavior this week.

The rest of this week: Previously scheduled House Intelligence Committee hearings and meetings are canceled as the committee deals with the fallout from Nunes's actions.

On Tuesday morning, The Washington Post reports that the Trump administration sought to block former acting attorney general Sally Yates from testifying to Nunes's committee this week. (Yates is the same official Trump fired in January when she refused to enforce his travel ban.)

Presidents have the authority to block information from Congress they deem vital to national security to keep secret, but the news is likely to fuel to charges that the White House is trying to hinder the investigation.