House Democrats sent interview requests for next week to three potentially major witnesses in the investigation: John Bolton, President Trump’s former national security adviser; John Eisenberg, the top lawyer for the National Security Council; and Mr. Eisenberg’s deputy, Michael Ellis. Mr. Bolton’s lawyer said he would not appear voluntarily.

A Foreign Service Officer assigned to the White House, Catherine Croft, told impeachment investigators today that Robert Livingston, a lobbyist and former Republican congressman, repeatedly told her that the U.S. ambassador to Ukraine should be fired because of what he saw as her association with Democrats . It’s not clear who may have hired him.

That ambassador, Marie Yovanovitch, testified earlier this month that Mr. Trump had been seeking her ouster since summer 2018 — even though, one of her bosses told her, she had “done nothing wrong.” Today’s testimony adds to the timeline of known attacks on Ms. Yovanovitch questioning her loyalty to Mr. Trump.

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The next phase of impeachment

On Thursday, the House will take a vote to set out rules and procedures for the impeachment inquiry. The Democrats produced the resolution after weeks of complaints by Republicans about the lack of such a vote. Here’s what will look new about the investigation:

It will introduce public hearings.

Representative Adam Schiff, the chairman of the House Intelligence Committee, will be tasked with holding public hearings, in addition to the closed-door interviews and evidence-gathering he has led so far. This will make it possible for the public to see what the investigators have found .

The public hearings could begin as early as the week of Nov. 11, and could feature some of the star witnesses of the investigation so far, including Ms. Yovanovitch and Mr. Taylor. They will be designed to eliminate the grandstanding of a traditional hearing: Instead of each member getting a brief turn to speak, the top Democrat and Republican — or staff lawyers — will question witnesses for extended blocks of time.

After that, the case will go to the Judiciary Committee.

The Intelligence Committee will produce a report on its findings and send it to the House Judiciary Committee, led by Representative Jerry Nadler, along with other evidence, including interview transcripts. The Judiciary Committee will have the power to seek additional materials, including hearing from witnesses.

If Mr. Nadler and the committee deem the evidence sufficient, they will recommend formal articles of impeachment for the House to vote on.

Republicans will have expanded powers.

The top Republicans on the Intelligence and Judiciary Committees — Representatives Devin Nunes and Doug Collins — will have the power to propose subpoenas for witnesses or documents. Mr. Trump’s legal team will also be able to cross-examine witnesses and present a formal defense of him.

But there’s a catch. If Mr. Schiff or Mr. Nadler object to the subpoenas Republicans want to issue, the full committee will vote, giving Democrats the ability to quash them. And the rules go even further: If the president stops witnesses from appearing, Mr. Nadler would have the power to stop the cross-examinations by Mr. Trump’s lawyers.

What else we’re reading

John Sullivan, the deputy secretary of state and President Trump’s nominee for ambassador to Russia, said at his confirmation hearing today that he was aware of a smear campaign designed to oust Ms. Yovanovitch, and that he suspected Rudy Giuliani was behind it.

Democrats in Congress were wary of a floor vote on the investigation. But they are now solidly behind the idea — even those who face difficult races in swing districts — in a reflection of Speaker Nancy Pelosi’s close hold on over her fractious caucus.

In a letter to the Army secretary, Senator Chuck Schumer, the Democratic leader, asked officials to protect Lt. Col. Alexander Vindman, who testified yesterday in the impeachment investigation, against retaliation. Mr. Vindman has come under attack by right-wing media outlets that questioned his patriotism. “It is incumbent on the Army to ensure that he is afforded the same protections as whistle-blowers,” the letter reads.

According to Politico, Colonel Vindman told investigators that Kashyap Patel, a National Security Council staffer and former adviser to Representative Devin Nunes, “misrepresented” himself to Mr. Trump as a Ukraine expert, despite a lack of relevant knowledge.

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