Philip Ewing

House Speaker Nancy Pelosi and her lieutenants are turning a new page in their impeachment inquiry this week based on a principle familiar to classics scholars: repetitio mater studiorum.

"Repetition is the mother of all learning."

Updated at 2:21 p.m. ET

White House officials filed the record of President Trump's now-famous call with his Ukrainian counterpart on a "different, more secure system" from the one they normally used, a key witness told House impeachment investigators.

President Trump's friend and political adviser Roger Stone is set to go on trial Tuesday in a proceeding that could reveal just how close Trump world got to the Russian interference in the 2016 election.

Jury selection is scheduled to commence following months of unusual public silence from Stone, who has been gagged by the judge in his case following a flap this year over his posts on social media.

President Trump's efforts to pressure the government of Ukraine didn't sit well with some key members of his administration.

One of them, whose identity remains unverified, felt strongly enough to write down his concerns about the president's actions in a whistleblower complaint to the intelligence community's inspector general.

But he wasn't the only one who spoke up.

House Democrats crossed the Rubicon this week and committed, for the record, to their impeachment inquiry. Although they said impeachment isn't a foregone conclusion, they tried to underscore again that this is serious.

Meanwhile, more confirmations of the facts of the Ukraine affair meant the end of the investigation process may now be in view — and public hearings could be coming next.

Here's what you need to know about the events of a historic week in Washington and what may be around the corner.

Lt. Col. Vindman and Mr. Morrison

Updated at 5:33 p.m. ET

House Democrats won an important victory in federal court on Friday when a judge ordered the Justice Department to surrender now-secret material from the Russia investigation — and, more broadly, validated the impeachment inquiry into President Trump.

Updated at 4:37 p.m. ET

The Justice Department's review of the origins of the Russia probe has become a criminal investigation, a source familiar with the matter confirmed to NPR.

It is unclear what prompted the shift from an administrative review to a formal criminal investigation, when the change took place or what potential crime is under investigation.

The change drew immediate criticism from Democrats, who have accused Attorney General William Barr of turning the Justice Department into a political weapon for President Trump.

President Trump outlined his Ukrainian pressure strategy directly to a top diplomat who was described as being charged with helping to execute it, another key diplomat told House investigators this week.

Meanwhile, sources in the Ukrainian capital told two U.S. news agencies that Kyiv had been pressured directly about American assistance in the spring.

So it was another big week in House Democrats' impeachment investigation of Trump and the Ukraine affair — and for Republicans' increasingly aggressive defense of the president.

Here's what you need to know.

House Democrats are set to resume their impeachment inquiry on Tuesday with a deposition from another diplomat who appeared uneasy with President Trump's strategy to pressure Ukraine for political help.

Ambassador William Taylor, who has been serving as the interim head of the U.S. diplomatic mission to Kyiv, is scheduled to talk behind closed doors with members and staff of the Intelligence, Foreign Affairs and Oversight committees.

President Trump deputized lawyer Rudy Giuliani to run a shadow foreign policy for Ukraine outside the State Department, witnesses told Congress this past week — and the White House said people should "get over it."

It has been a busy week. Here's what you need to know about the latest in the Ukraine affair and the impeachment investigation.

Mister mayor

Giuliani has been an important figure in Trump world for years, but what investigators heard was how central he was in the plan to get Ukraine's government to launch investigations that Trump wanted.

Each week — and some days, it seems, each hour — brings more clarity to the picture of the Ukraine affair and the political crisis it sparked in Washington over impeachment.

But some of the biggest questions still don't have answers.

Here's a look at where the saga stands, what investigators want to learn and what major decisions still must be reached before the fever breaks.

The Ukraine affair

No one disputes the basic outlines of the Ukraine affair, including President Trump:

Updated at 6:45 p.m. ET

House Speaker Nancy Pelosi did not rule out a vote by the full chamber on its impeachment inquiry into President Trump — but she restated her belief on Friday that none is required for it to move ahead.

Pelosi, D-Calif., said on a trip to Atlanta that she was unmoved by calls from the White House for a full vote. Trump said earlier in the day that he would send a letter to the speaker, which was expected to demand action by the full House.

House Democrats are set to launch a new phase of their impeachment inquiry on Thursday when former Ambassador Kurt Volker, until recently a top State Department representative to Ukraine, is scheduled to meet with investigators.

Then, on Friday, the intelligence community's inspector general, Michael Atkinson, is due on the Hill.

More witnesses are expected next week, all for depositions behind closed doors with members of Congress and their staff.

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.

Updated at 12:08 p.m. ET

The nation's top spy told lawmakers on Thursday that he supports the whistleblower whose complaint sparked the Ukraine affair but said he struggled to deal with how to handle the case inside the Trump administration.

Acting Director of National Intelligence Joseph Maguire told the House intelligence committee in an open hearing that he believed the whistleblower and the spy world's inspector general had acted in good faith and that he has tried to handle a unique situation as best he could.

Updated at 5:25 p.m. ET

President Trump told Ukraine's president that "a lot of people want to find out" about the activities of former Vice President Joe Biden's family in Ukraine and asked its leader to be in touch with lawyer Rudy Giuliani and Attorney General Bill Barr.

That's according to a briefing for correspondents about the contents of the July 25 phone call, on Wednesday at the Justice Department.

Updated at 5:25 p.m. ET

President Trump and his opponents jockeyed for advantage on Monday as Washington girded for a drawn-out conflict over the White House and Ukraine.

Trump and his aides sought to throw the spotlight on former Vice President Joe Biden and his son, Hunter, who they said might be connected with what they called "corruption" in Ukraine — although Biden's camp insists those allegations have been debunked.

Updated at 4:53 p.m. ET

President Trump's former campaign manager jousted with House Democrats on the Judiciary Committee Tuesday in a combative hearing that each side hoped might strengthen its narrative about the legacy of the Russia imbroglio.

President Trump spiked the peace negotiations for a war he's desperate to end and sacked the national security adviser who shaped much of his foreign policy in Asia and the Middle East.

Where does the Trump administration's foreign policy go from here?

Until Saturday, one path, at least, appeared clear: Washington was inching closer to some kind of agreement with the Taliban to end the 18-year conflict in Afghanistan.

Updated at 4:57 p.m. ET

President Trump has fired national security adviser John Bolton, the lifelong proponent of American hard power, after months of division between the men over the direction of foreign and national security policy.

Trump announced the news Tuesday on Twitter.

Americans are preparing more than ever to safeguard voting as the nation looks ahead to the Democratic primaries and the general election next year.

What no one can say for certain today is whether all the work may turn out to be superfluous — or whether it'll be enough.

Security experts have warned about the prospect of a new era of high quality faked video or audio, which some commentators worry could have deeply corrosive effects on U.S. democracy.

Here's what you need to know.

What are "deepfakes?"

Foreign interference didn't begin in 2016. It didn't end with that election. And U.S. officials expect it to remain an issue through the 2020 elections as well.

Here's what you need to know.

Voting systems in the United States have come a long way since the hanging chads of the 2000 recount in Florida — but now cybersecurity is as big a concern as ballot fidelity.

Here's what you need to know.

The good news

Updated at 3:11 p.m. ET

Former FBI Director James Comey violated official policy in the way he handled his memos describing his exchanges with President Trump, an investigation concluded — but Comey won't be charged.

Justice Department Inspector General Michael Horowitz conducted the investigation into Comey's actions and then referred his results to prosecutors.

President Trump defended the idea of buying Greenland — derided by critics within the United States and rejected by Denmark, which controls it — in part by saying the idea first came from President Harry Truman.

Updated at 4:32 p.m. ET

President Trump abruptly dropped his intention to nominate Rep. John Ratcliffe, R-Texas, to serve as director of national intelligence on Friday.

Updated at 2:23 p.m. ET

The Federal Election Commission is considering proposed new rules to outlaw exchanges like the one that took place when a Russian delegation visited Trump Tower in 2016 to offer Donald Trump's campaign "dirt" on Democrats.

Although U.S. law already forbids contributions from foreigners to American political campaigns, President Trump has said that the meeting taken by his son Donald Trump Jr. and others was business as usual and that everybody in politics accepts "opposition research."

Updated 1:35 p.m. ET

Rep. John Ratcliffe is President Trump's choice to become the next top leader of the U.S. intelligence community.

The Texas Republican thanked Trump on Twitter following the president's earlier announcement, also on Twitter, that Ratcliffe is his nominee to replace outgoing Director of National Intelligence Dan Coats.

Former special counsel Robert Mueller did what Democrats wanted him to do on Wednesday — the question now is how much difference that may make.

Mueller's hearings did not feature a telegenic star who could deliver a message as exuberantly as President Trump's opponents hoped.