House Democrats gave themselves political wiggle room when they launched their impeachment inquiry without holding a floor vote, but that procedural strategy also left room for the White House and a federal judge to question the legitimacy of the push.

The White House, in a letter Tuesday criticized as advancing a legally flimsy argument, told the House it would not participate in an impeachment inquiry that hasn’t been authorized by the full House — which they argue means it isn’t “a valid impeachment proceeding.”

[Judge questions keeping Mueller grand jury materials from House]

And a federal judge, hearing arguments Tuesday about whether the House Judiciary Committee should get grand jury materials from the special counsel report from Robert S. Mueller III as part of an impeachment inquiry, questioned when she could know such an inquiry had begun if there wasn’t a floor vote.

“Where are you suggesting I should draw lines?” Chief U.S. District Judge Beryl A. Howell asked House General Counsel Douglas Letter.

Speaker Nancy Pelosi of California could foreclose such attacks and questions with a floor vote, something Howell said would make it “easier for all of us.” Pelosi appears to have the support to pass a resolution authorizing the inquiry. She hasn’t ruled it out.

But for now, House Democrats have argued in the media, in letters to the Trump administration and in the courtroom that Pelosi’s announcement of an “official impeachment inquiry” at a news conference in September means it has started. House Republicans disagree.

That procedural ambiguity underscores the complex politics of impeachment, where Pelosi wants to simultaneously legitimize the House’s constitutional role to investigate the president for wrongdoing and play politics at the same time, Joshua Huder, a senior fellow at Georgetown University’s Government Affairs Institute, told CQ Roll Call.

“Speaker Pelosi could open a formal inquiry today with 226 Democrats but this would create a bipartisan coalition against impeachment, undercutting the legitimacy of the investigation and playing into President Trump’s messaging that the investigation is a sham,” Huder wrote Wednesday.

“This is why the White House made an absurd constitutional argument, linking their oversight compliance with a formal impeachment inquiry vote,” Huder wrote. “They understand the vote would divide a small number of Democrats from the broader majority, undermining the investigation’s credibility.”

Rep. Ro Khanna, D-Calif., said Tuesday on CNN that the House won’t vote until there are articles of impeachment — and that there is no need do so. He also said that such a vote to open an impeachment inquiry would just mean “the president would just have a different excuse” to not cooperate.

“The calculation is the speaker wants members to go on the record once, after a full case has been made, after we have collected whatever evidence we can,” Khanna said. “But we’re not going to do it prematurely, and we’re not going to do it on the president’s timeline, especially when the House rules are very clear the chair of the Judiciary can start this inquiry.”

White House Counsel Pat Cipollone did not attempt to mask the Trump team’s desire to make the letter more of a political document than a legal one. But the issue will start to pop up in lawsuits to enforce congressional subpoenas for documents and testimony related to Trump investigations.

An impeachment inquiry can add weight to the argument that the House needs the information requested in a subpoena for the process of impeachment, a power the Constitution delegates solely to the House.

That’s especially true if Democrats want to litigate to enforce subpoenas related to Trump’s dealings with Ukraine now at the heart of the impeachment probe, since the White House now says it won’t cooperate.

And Trump predicted Wednesday that the letter likely will become a “Supreme Court case.”

A 1993 decision from the Supreme Court seems to give Congress the power to create its own rules for impeachment — but a question could be whether the House actually had impeachment rules without a floor vote on opening an inquiry.

The House can use the letter to show judges the breadth of the Trump administration’s obstruction to congressional oversight — which could short-circuit any way for judges to ask the two sides to work it out without the court system, said University of Texas law professor Steve Vladeck.

The argument in the White House letter, Vladeck said, will elevate “this from a series of squabbles to a full-on, head-on confrontation.”

The issue of when the House is in an official impeachment inquiry came up Tuesday in federal court. Rep. Doug Collins of Georgia, the ranking member of the Judiciary Committee, filed a brief in the House application to obtain normally secret grand jury material to point out that prior presidential impeachments were authorized with a floor vote.

Collins wrote that the House would be able to get the grand jury material if the full House voted to authorize a formal impeachment proceeding, but that hasn’t happened.

“Without an explicit authorization from the full House, the Court has no determinative measure of when an official impeachment proceeding has begun and when the Committee is merely exercising its normal oversight powers,” Collins wrote. “Votes — not words or press conferences by Members, the Chairman, or the Speaker — are the mechanism through which Congress acts.”

Howell asked about that Collins argument, saying he’s “got a very clear line.” Letter, the House general counsel, responded that the House is in a formal impeachment inquiry “because the House says it is. The speaker of the House has said it is.” And lawmakers are spending “one heck of a lot of time” on impeachment, Letter added.

There is also a resolution (H Res 430) that authorized the Judiciary Committee to seek the grand jury material under its Article I powers — which includes impeachment, Letter said.

Howell has yet to rule on whether to give the Judiciary Committee access to the grand jury material.