The Trump administration’s decision to block a key witness from testifying in the Ukraine-related impeachment inquiry isn’t a concern for House Democrats. In fact, they say that move gives them even greater ammunition for President Donald Trump’s impeachment.

Here’s why: keeping US Ambassador to the European Union Gordon Sondland away from congressional investigators on Tuesday may only increase perceptions that Trump aims to obstruct justice. While Democrats will subpoena Sondland and others the White House could try to stop from giving testimony, they say the fact that they have to compel appearances is damning enough.

“The failure to produce this witness, the failure to produce these documents, we consider yet additional strong evidence of obstruction of the constitutional functions of Congress,” House Intelligence Committee Chair Adam Schiff (D-CA) told reporters on Tuesday.

Sondland isn’t the only administration official Trump’s allies want to block from testifying in the inquiry on Trump’s effort to get Ukraine to investigate former Vice President Joe Biden, seemingly in exchange for military aid. Also on Tuesday, the White House sent a scorching eight-page letter to leading House Democrats saying they would no longer cooperate with the investigation because it’s a political hit job.

“You seek to overturn the results of the 2016 election and deprive the American people of the President they have freely chosen,” Pat Cipollone, the chief White House counsel, wrote. “Your highly partisan and unconstitutional effort threatens grave and lasting damage to our democratic institutions, to our system of free elections, and to the American people.”

When Vox asked a senior administration official if the White House’s stance amounted to obstruction, the official shot down such a concern. “Asserting your right under the Constitution cannot ever be properly framed as obstruction of justice. They [Democrats] may try to make that argument politically, but it’s not a legal argument.” The official wouldn’t say under what circumstances the White House would participate in the inquiry.

That won’t bother Democrats one bit, because in a sense this is all a win-win for them: They either get more evidence from those involved in the whole Ukraine debacle, or they go after Trump on obstruction.

“I would be surprised if there were not at least one article of impeachment that is obstruction of justice,” House Judiciary Committee Vice Chair Mary Gay Scanlon told Vox in a Tuesday interview. “In some sense, the more obstruction there is, the more quickly this moves. It does feel like continuing coverup.”

This strategy — “evidence or obstruction,” let’s call it — negates the need for a lengthy legal fight. Some Democrats hope to decide on whether to move forward with articles of impeachment by Thanksgiving, and they know they couldn’t possibly take on the Trump administration in court with such a tight timeline. So instead, House Democrats have chosen to let Trump pick his poison.

“The move is to try to get as many key witnesses to show or be blocked as possible, and then decide how to move forward with that collection of evidence,” a senior House Democratic aide told Vox. “But remember: between the whistleblower complaint, transcript summary, and the text messages, we already have a body of damning evidence.”

Why Democrats say Trump stonewalling them helps impeachment

“As if often the case with the executive, the coverup is the crime,” Linda Fowler, a congressional and legal expert at Dartmouth College, told Vox. “That’s what usually gets presidents in trouble.”

Democrats tend to share that sentiment, and only more so after Sondland didn’t testify on Tuesday.

A State Department lawyer told Vox that Secretary of State Mike Pompeo or Trump don’t have the right to stop Sondland from testifying. That makes sense, as a 1912 federal law stipulates “[t]he right of employees, individually or collectively, to petition Congress or a Member of Congress, or to furnish information to either House of Congress, or to a committee or Member thereof, may not be interfered with or denied.”

Sondland, per his lawyer, said he wanted to chat with congressional investigators. But after he handed over texts on his personal device to the State Department, the attorney received a middle-of-the-night call to inform him the ambassador couldn’t speak on the Hill.

Democrats didn’t take kindly to that. “These actions appear to be part of the White House’s effort to obstruct the impeachment inquiry and to cover up President Trump’s misconduct from Congress and the American people,” the three chairs of the House committees leading the impeachment inquiry — Schiff, Eliot Engel (D-NY), and Elijah Cummings (D-MD) — said in a joint statement.

In response, they plan to subpoena Sondland in an effort to get him to testify and hand over the relevant information, especially his text messages. Asked if the ambassador would then have to comply, the senior House Democratic aide said that’s where things could get tricky: “Congress would argue ‘yes,’ the administration would argue ‘no.’ Sondland would probably defer to administration, and it would need to get settled in a long court battle.”

But Democrats don’t want to get bogged down. Court cases take a long time, and engaging in a lengthy legal battle will take this matter well past Thanksgiving — the time Democrats want to make a decision on whether or not to impeach Trump. Many of Democrats’ other oversight investigations are waiting for a court decision before they can proceed. And since they’re already satisfied with the information they have, they can go forward with that while arguing that keeping witnesses away from Congress merits its own article of impeachment.

“The third article of impeachment against Richard Nixon was obstruction of the impeachment investigation by refusing to comply with subpoenas,” the senior House aide said. “If the White House continues to block material witnesses from being questioned by Congress, that itself may become an impeachable offense.”

It’s worth noting that the House inquiry isn’t a trial, so some legal experts say the president can’t obstruct justice outside a legal process. But others, like Fowler, note that stopping Congress from its right to investigate the president could be seen as obstruction.

“It’s obstruction of justice in that it’s stopping a witness from appearing before a legitimate body of inquiry,” she told Vox. It’s why she’d offer the president different legal advice than he’s currently receiving: “If Trump had a good lawyer, he’d let these people testify. They can always limit their testimony.”

Congress will hit the ground running when they return from break next week

Next week, Congress will return from a two-week recess with a long to-do list. House Democrats have a lot to get done in a fairly tight timeline; some want to ready articles of impeachment by Thanksgiving, and send them to the full House in December, allowing for a vote by the end of the year.

“I think it’s everyone’s intention here to get this done in 2019,” Rep. Jamie Raskin (D-MD), a member of House Judiciary, recently told reporters.

House Democratic leadership won’t say much about a specific date, beyond making it clear they want the committees to move as quickly as possible. But Democrats believe they have found a smoking gun with the Ukraine scandal; they have no reason to play the Trump administration’s game and let their subpoenas languish in court.

“I would say it is going to be very soon that we have to decide whether we have enough evidence in front of us,” Rep. Pramila Jayapal (D-WA), a House Judiciary Committee member, told Vox. “The timeline has to be as rapid as possible, given the threats to national security. We have to dot all the i’s and cross all the t’s.”

The Trump administration is pushing back hard on this timeline; in a number of their responses to congressional subpoenas, officials have argued it’s too tight of a turnaround. Other times, they just haven’t responded at all.

And public sentiment appears to continue to shift in Democrats’ favor; a Washington Post-Schar School poll released Tuesday shows 58 percent of Americans support the House’s decision to launch an impeachment inquiry, compared to 38 percent who don’t. And 49 percent say the House should go further and remove the president from office, the poll found. Polls have found the number of independents and Republicans who support an inquiry growing as well.

“In spite of the White House spin, our message is getting out because it is about those most fundamental constitutional values people hold,” Jayapal said.

The six committees tasked with investigating the Trump administration are already very familiar with the executive branch trying to block their access to information. The Trump administration has been stonewalling congressional committees’ requests for documents and witnesses for months. And former special counsel Robert Mueller famously outlined 10 possible obstruction of justice episodes in his Trump-Russia probe — noting that while he couldn’t say the president committed a crime, he couldn’t acquit Trump of one, either.