House Speaker Nancy Pelosi has called for House Democrats to "proceed with articles of impeachment" against President Trump, but questions remain over whether she has secured enough Democrats to vote for impeachment as the effort barrels forward at breakneck speed.

Pelosi, during her televised remarks about impeachment on Thursday, did not suggest any particular timeline for a vote, saying only, "We will proceed in a manner worthy of our oath of office."

The timing of such a vote could be indicative of whether Pelosi has enough Democrats to vote to impeach: Pelosi is a master at reading her caucus. If she has the votes, she’ll likely give the green light to impeach on the floor. If she doesn’t have the votes, impeachment could wait -- conceivably until the New Year.

A major milepost, though, could come at 5 p.m. Friday: Democrats have said the Trump administration has until the close of business to decide if it will cooperate with the investigation or try to defend the president. If the administration says it’s willing to play, then impeachment could stretch out a bit. If not, Democrats may operate under a compressed timeframe.

PELOSI CALLS FOR ARTICLES OF IMPEACHMENT AGAINST TRUMP: 'NO CHOICE BUT TO ACT'

"This is a hard vote to make one way or the other," Rep. Jeff Van Drew, D-N.J., who opposed the inquiry before it began and remains skeptical of the impeachment efforts, told reporters Thursday.

A simple majority -- 216 of 431 members -- is needed to impeach. There are 233 Democrats, meaning that presuming anti-Trump independent Rep. Justin Amash backs impeachment, Democrats can lose 18 of their own and still impeach the president

A member of Pelosi’s leadership team told Fox News this week that the backlog of bills up this month in the House “works against” a December impeachment vote, explaining that impeachment “doesn’t fit the holiday spirit.”

Van Drew was one of just two Democrats who opposed the inquiry, alongside Minnesota's Collin Peterson, but Republicans are hoping that the 31 Democrats from districts that supported Trump in 2016 could be the key to defeating the impeachment effort.

Sensing a possible opening, the Republican National Committee (RNC) has ramped up the pressure on these Democrats in pro-Trump districts. As reported by The Daily Caller, the RNC is running ads urging voters to pick a lawmaker who “won’t waste taxpayer $$$ on partisan impeachment.”

Wall Street Journal Editorial Page Deputy Editor Dan Henninger told Fox News that some of these 31 Democrats are "really reluctant to take this vote," especially at this point in time.

"Do those Democrats really want a vote on virtually Christmas Eve?" he asked.

Henninger predicted that an impeachment trial could go into February. Not only could that slow down the momentum Democrats have built with the swift pace of the inquiry in recent weeks, it also places a burden on senators who will be in the thick of the presidential primary season. The Iowa caucuses are set for Feb. 3, with the New Hampshire primary Feb. 11, and contests in Nevada and South Carolina later that month.

While Democrats may use impeachment as an anti-Trump talking point on the campaign trail, candidates -- including Sens. Elizabeth Warren, D-Mass.; Bernie Sanders, I-Vt.; Amy Klobuchar, D-Minn.; Cory Booker, D-N.J., and Michael Bennet, D-Col. -- could end up spending valuable days of the primary season torn between their campaigns and a Senate trial should Trump actually be impeached.

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An impeachment trial at that stage of the game would put the senators at a disadvantage, while candidates such as South Bend, Ind. Mayor Pete Buttigieg, former Vice President Joe Biden and former New York City Mayor Michael Bloomberg would be free to continue their efforts.

"This impeachment is beginning to overwhelm the real politics that the Democrats should be interested in," Henninger said, "which is trying to get themselves a presidential nominee."

On Thursday, Pelosi delivered a statement urging House Judiciary Committee Chairman Rep. Jerrold Nadler, D-N.Y., to proceed with impeachment after a hearing a day earlier featured constitutional scholars presenting arguments for and against it.

“The president leaves us no choice but to act, because he is trying to corrupt, once again, the election for his own benefit," Pelosi said regarding Trump's request to have Ukraine announce an investigation of Biden and his son Hunter.

Amid the impeachment effort, lawmakers also have to deal with a looming government shutdown that could take effect Dec. 20 unless Congress passes spending legislation to avoid it. With just over two weeks to do so -- and holidays coming soon after -- impeachment could find itself on the House's back burner until the new year.

During a press conference in the hours following her impeachment announcement, Pelosi fielded a question about the timeline of the impeachment process, stating that "we feel comfortable with all of the time that has gone into this." She pointed out that it has been two and a half years since Robert Mueller was appointed as special counsel "and all that has transpired since then."

Following Pelosi's announcement, Senate Majority Leader Mitch McConnell, R-Ky., took Democrats to task for not putting pressing legislative matters ahead of impeachment.

"We've argued that American families deserve better than this partisan paralysis where Democrats literally obsess over impeachment and obstruct everything else," McConnell said on the Senate floor. "This very morning, for example, the Speaker gave a speech on national television to push forward her rushed and partisan impeachment. Not one word, not one word on the outstanding legislation the American people actually need. Nothing on USMCA or the NDAA or funding for our armed forces. It's all impeachment, all the time."

Pelosi responded to this during a news conference in the hours following her impeachment announcement by stating, "No, we have 275 bipartisan bills on your desk."

Senior House leadership sources have acknowledged to Fox News that they think it would be a challenge to have a proper debate and rush articles of impeachment through the Judiciary Committee and to the House floor before Christmas, while also working to avoid a shutdown. Pelosi indicated Thursday that the House has a number of bills on the agenda in the coming week, pointing to bills including legislation dealing with insider trading and voting rights.

DEM REVERSES COURSE ON IMPEACHMENT AGAIN, NOW SUPPORTS AFTER SAYING IT HAD NO VALUE

"It's too complex," a senior member of House Speaker Nancy Pelosi's leadership team told Fox News earlier this week.

That complexity could be increased by the need to carefully draft articles of impeachment that would draw enough support to pass in a vote by the full House of Representatives. A Capitol Hill source told Fox News that committee members were looking to Wednesday's testimony from law professors to formulate articles that would have the best chance of passing.

Republicans have united behind Trump against the impeachment efforts, meaning Democrats cannot afford to lose many votes from their own party.

Some Democrats, like Van Drew, remain skeptical of the effort. "Is this really an impeachable situation?" Van Drew asked in an interview with USA Today, noting the rarity of presidential impeachment in American history, and the fact that no president has ever been removed via that process.

"At the end of the day, nobody's ever been convicted," he said. "There's a reason for that. Our founding fathers had tremendous concern with the idea of impeachment. The idea of taking an elected leader regardless of how good or poor you think that elected leader is, out of office and disenfranchising hundreds of millions of voters does a lot that isn't so good for this country."

READ: HOUSE DEMOCRATS' IMPEACHMENT REPORT

Fox News' Chad Pergram, Gillian Turner, Adam Shaw, and Gregg Re contributed to this report.