WASHINGTON — The House Judiciary Committee took a big step Thursday morning in its ongoing investigation into whether to recommend the filing of articles of impeachment against President Donald Trump, passing a resolution that set procedures and rules for future impeachment investigation hearings.

The resolution passed along party lines, 24-17.

"Some call this process an impeachment inquiry. Some call it an impeachment investigation. There is no legal difference between these terms, and I no longer care to argue about the nomenclature," House Judiciary Committee Chairman Jerry Nadler, D-N.Y., said in his opening statement Thursday.

"But let me clear up any remaining doubt: The conduct under investigation poses a threat to our democracy. We have an obligation to respond to this threat. And we are doing so."

Earlier this week, Nadler told NBC News that the purpose of the resolution was to put into effect "certain procedures to make that investigation more effective," a necessary move given that "the inquiry is getting more serious."

Under the resolution, which does not need to be approved by the full House, Nadler can designate hearings run by the full committee and its subcommittees as part of the impeachment investigation. The committee's lawyers are also able to question witnesses for an additional hour beyond the five minutes that are allotted to each member of Congress on the panel.

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Additionally, the president’s lawyers will be able to respond in writing to evidence and testimony presented to the committee, and evidence can be received in closed session.

The top Republican on the Judiciary Committee, Rep. Doug Collins, R-Ga., attacked the resolution, insisting it was not enabling Nadler to do anything he wasn't already empowered to do.

"The Judiciary Committee has become a giant Instagram filter," making it appear that something greater than what is happening has taken place, Collins said.

The first hearing that the Judiciary Committee has scheduled in which the procedures will be in effect is slated for Sept. 17, when former Trump campaign manager Corey Lewandowski is scheduled to testify. The committee has also subpoenaed Rick Dearborn, former White House deputy chief of staff for policy, and Rob Porter, former White House staff secretary, to testify that day as well. The White House has previously blocked key witnesses from appearing before Congress.

While Democrats have not set a deadline for recommending articles of impeachment, staffers have suggested a pre-election year timeframe.

“I think it’s fair to say it’s the goal by the end of the year, but it’s not a hard and fast deadline. That’s our goal,” the aide said.

Nadler himself has been less definitive on a potential timeline, telling NBC News this week: “I don't know. I'd like to do it rather rapidly.”

President Donald Trump speaks at the White House on Sept. 11, 2019. Alex Wong / Getty Images

As the committee meeting was underway, Trump tweeted, “We can’t beat him, so let's impeach him!”, a quote he attributed to Rep. Al Green, D-Texas, one of the first and most fervent supporters of impeachment. It's not clear whether Green has ever actually said that; in May, he told MSNBC, "I'm concerned that if we don't impeach the president, he will get re-elected."

In response to Trump, Green tweeted, "Because no one is above the law, we must impeach, and if the Senate does not convict, we will defeat. @realDonaldTrump You will NOT have a second term!"

Because no one is above the law, we must impeach, and if the Senate does not convict, we will defeat. @realDonaldTrump You will NOT have a second term! #ImpeachNow https://t.co/PBDB2Dba6V — Congressman Al Green (@RepAlGreen) September 12, 2019

There has been significant confusion among lawmakers about the status of the investigation. Nadler said before Congress’s six-week summer recess that the panel was already in the midst of conducting an impeachment inquiry. Other lawmakers have said that that hasn’t been made clear.

Nadler reiterated on Thursday that legally, there is no difference between an impeachment inquiry and impeachment investigation and said beginning next week, the committee would start an aggressive series of hearings.

Yet House Speaker Nancy Pelosi has not backed down on her public stance shying away from full-blown impeachment.

“The public isn’t there on impeachment,” she told House Democrats during a conference call in late August — though she didn’t close the door on the possibility of moving forward in the future.

Asked Monday if she agreed with Nadler's statement that impeachment proceedings have already been taking place, she avoided answering directly. “I really don't know what the chairman said, I do know that we have been on a path of investigation and that includes the possibility [of] legislation or impeachment,” she told reporters.

Pelosi also said she had signed off on Nadler’s decision to hold the vote on the resolution Thursday to establish the panel's impeachment investigation procedures.

“We have been in an impeachment investigation in that we have been investigating whether or not the Judiciary Committee is going to recommend articles of impeachment to the full House,” Rep. Pramila Jayapal, D-Wash., a member of the Judiciary panel, told reporters this week. “This allows us to formalize that and also allows us to utilize slightly different procedures that will be helpful to us as we go through an investigation because the five-minute back and forth is very difficult.”

The Congressional Progressive Caucus, of which Jayapal is a co-chair, took an official position Tuesday supporting an impeachment investigation.

More than half of the House Democratic caucus — 134 out of 235 — have publicly backed an impeachment inquiry, including 17 out of the 24 Democrats on the Judiciary Committee.

Impeachment was a major issue during congressional town halls over the August congressional recess as a significant number of House Democrats, especially freshmen members, continued to wrestle with the issue.

Republicans continued to argue that Democrats need to take an official vote to begin any type of inquiry.

“The House of Representatives is not engaged in formal impeachment proceedings, as House Democrat leaders continue to note. Formal impeachment proceedings have always been authorized by a vote of the full House, which Speaker Pelosi has been careful not to allow,” the top Republican on the House Judiciary Committee, Rep. Doug Collins, R-Ga., said Wednesday, calling the panel's planned Thursday action “a meaningless reiteration of existing committee authorities, allowing the chairman to keep this story in the news when moderate Democrats simply want it to go away.”