MARY LOUISE KELLY, HOST:

This evening, House Democrats have sent a subpoena to the White House. They're looking for documents related to the impeachment inquiry, and they have set a deadline of October 18. Earlier today lawmakers interviewed Michael Atkinson. He is the inspector general of the intelligence community. That was behind closed doors.

AUDIE CORNISH, HOST:

This comes as the president and the speaker of the House spar over whether or not to have a vote on the inquiry itself. NPR political reporter Tim Mak joins me now from the Capitol.

Hey there, Tim.

TIM MAK, BYLINE: Hey there.

CORNISH: Atkinson was on the Hill. This is the second time in the last two weeks. So what are members interested in learning from him?

MAK: So the last time Atkinson was on Capitol Hill two weeks ago, he was unable to answer questions about what was then a nonpublic complaint. But now the administration has made that complaint public, and lawmakers are asking why the IG, the inspector general, found the whistleblower's complaint credible and urgent. Congressman Adam Schiff - he chairs the House Intelligence Committee - said, quote, "We can see that the IG's determination was correct in both respects. Trump pressured a foreign leader to interfere in the 2020 election by investigating a political opponent," end quote.

And even while the briefing was - with Atkinson was underway, House committees put out a demand that expands their inquiry. They want documents from Vice President Mike Pence that touch on his role in this story, and they've set an October 15 deadline. Pence's office, meanwhile, is pushing back, saying that the request was, quote, "partisan" and, quote, "does not appear to be a serious request."

CORNISH: You use the plural committees. What is the state of play right now for the broader impeachment inquiry?

MAK: So generally speaking, Republicans and Democrats don't really disagree about the central fact here, that the president asked the Ukrainian government to investigate Joe Biden and Biden's son. The president's supporters, however, have said that this is not an impeachable offense, and they have also seized on news reports that the whistleblower got in touch with the House Intelligence Committee before filing his or her complaint with the inspector general. President Trump and Republicans are further arguing that the House should not proceed with the impeachment inquiry without a vote of the whole House.

There is nothing in the Constitution, the law or House rules that requires this, but it does break some precedent with previous impeachment proceedings, for the House not to have a vote on the launching of this inquiry. Asked about it today by reporters, House Speaker Nancy Pelosi had this to say.

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NANCY PELOSI: You know who's most scared of having a vote on the floor? The Republicans. See - every time they say something, turn it upside down. We want to have a vote. No, our numbers are very comfortable with a vote. They're the ones who are going to have to answer for it in suburban America.

MAK: So Pelosi has been saying a vote isn't required, but she's not ruling out doing it at some point.

CORNISH: What are the next steps in the inquiry?

MAK: So more depositions are scheduled next week as part of the Democratic effort to investigate this issue. While some interviews with State Department officials have been scheduled by the committees, they have not been confirmed by the participants yet. One deposition that is confirmed - that's an interview with the former U.S. ambassador to Ukraine, Marie Yovanovitch. You'll recall that she was abruptly recalled from her post in May amid the Trump administration's attempts to pressure the Ukrainian government.

Democrats on the Intelligence Committee will also be looking into further leads surrounding texts they released to the public late last night. Those are texts provided to the committees by Kurt Volker. He's the former U.S. special envoy to Ukraine. And they show diplomats debating whether it was appropriate for the administration to pressure Ukraine for political investigations.

CORNISH: That's NPR political reporter Tim Mak.

Tim, thanks for your reporting.

MAK: Thanks a lot. Transcript provided by NPR, Copyright NPR.

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