Rep. Ben Ray Luján (N.M.) speaks at the Capitol on July 25. (Andrew Harnik/AP)

Congress isn’t in session, but over the past month, more than two dozen House Democrats — including on Monday the No. 4 House Democrat, Rep. Ben Ray Luján (N.M.) — are publicly saying they support an impeachment inquiry into President Trump. The top three leaders still haven’t.

“I support moving forward with an impeachment inquiry, which will continue to uncover the facts for the American people and hold this president accountable,” Luján said in a statement Monday, citing the report by former special counsel Robert S. Mueller III.

What’s going on?

To some extent, these lawmakers are getting themselves over to where reality is. An impeachment inquiry is already happening and has been for weeks, according to court filings by the House Judiciary Committee and recently confirmed by its chairman, Rep. Jerrold Nadler (D-N.Y.).

“This is formal impeachment proceedings,” he told CNN on Aug. 8.

We are still trying to figure out what that means practically for Nadler’s committee, which takes the lead on impeachment. Will they write up articles of impeachment as soon as Congress is back in session in September?

Or will they continue much the same as before Nadler said the “I” word: battle with Trump over witnesses and documents to hold hearings and not ever hold a vote on impeachment? Some House Democratic aides close to the process told The Fix that they aren’t sure, either.

Of the Democrats who have recently supported an impeachment inquiry, it’s likely that they also want to be where the majority of the caucus is. Of the 235 House Democrats, a Washington Post tally finds 125 support an impeachment inquiry, which is well more than half.

We reached the halfway mark just days after lawmakers went home for a month-long break — a historic moment in itself that underscored how unstoppable this movement has been since the Mueller report was released in April.

For Luján, who holds a powerful position in House leadership and is someone several newly elected Democrats look to for guidance, there was no one thing in particular that tipped him to an impeachment inquiry. He has been there for a while, a senior Luján aide told The Fix, but didn’t want to get out in front of moderate House Democrats he helped elect last year as head of House Democrats’ campaign arm.

“Now was just the right time,” said the aide, who requested anonymity to speak more candidly.

Luján is the highest-ranking House Democrat to support it, but he’s also not the first member of House Democrats’ leadership to go on the record about it and thus directly oppose House Speaker Nancy Pelosi’s (D-Calif.) stated concerns. Reps. Katherine M. Clark (Mass.) and David N. Cicilline (R.I.) already have done so. Luján is also leaving the House to run for Senate next year. (Luján’s aide said this didn’t factor into his decision. New Mexico, a purple-blue state, isn’t necessarily clamoring for impeachment, and Luján does have a primary challenger from the left, but she isn’t well funded.)

For the 26 lawmakers who have said they support an inquiry since Congress took off in late July, going back home for an extended period and hearing from their constituents seems to have convinced them that it’s the right thing to do or has, at least, given them the confidence to say so.

There’s evidence that those who support impeachment are more likely to get ahold of their lawmakers and let them know.

Rep. Katie Hill (D-Calif.) doesn’t (she’s a Pelosi ally) support impeachment, but The Post reported in June that her office “is drowning in calls urging her to press for impeachment, even while representing a Republican-leaning district that is home to the Ronald Reagan Library.”

Whether to support an impeachment inquiry is a huge and hugely personal decision. Luján’s public announcement may sway even more Democrats to do it because he’s such a high-profile figure in the House. But as the days tick by, more and more House Democrats are coming to their own conclusion that Congress needs to seriously consider whether to impeach Trump.

JM Rieger contributed to this report.