House Judiciary Committee ranking member Rep. Jerrold Nadler (D-N.Y.) said on Dec. 13 that President Trump is trying to "discredit the free press and the Department of Justice." (House Judiciary Committee)

To fill their top spot on the House Judiciary Committee, Democrats had a choice between experts in two critical policy arenas — a constitutional-law ace with firsthand experience battling Donald Trump, and an architect of sweeping immigration legislation.

By a wide margin, they chose the constitutional-law expert. Why? To ready themselves for a battle with President Trump that could end with impeachment proceedings.

The selection of Rep. Jerrold Nadler (D-N.Y.) as the ranking Democrat on the Judiciary Committee was the clearest sign yet of how seriously House Democrats consider the possibility of a full-blown constitutional showdown with Trump.

You wouldn’t know it from how many of them talk. When it comes to the i-word, most Democrats have walked a tightrope — with even Nadler hesitant to mention impeachment in interviews before votes were cast Wednesday.

Leaders have cautioned the rank and file not to push for impeachment, because the public might view it as an overreach. The House’s few remaining moderate Democrats from swing districts have regularly warned the party’s liberal flank against making the 2018 midterm elections about Trump or the investigations into his presidential campaign.

Rep. Jerrold Nadler (D-N.Y.), alongside House Judiciary Committee Chairman Bob Goodlatte (R-Va.), left, on Capitol Hill last month. (J. Scott Applewhite/AP)

“Look, Robert S. Mueller III is on the case,” said Rep. Cheri Bustos (D-Ill.), from a western Illinois district that swung to Trump last year. “We’ve got to let him do what he’s going to do and let the facts go wherever they’re going to go. In the end the truth comes out, but I don’t think we need to rush anything more than that.”

Bustos had a one-word reply when asked what issues Democrats need to focus on in the next 11 months: “Jobs.”

Yet Nadler anchored his candidacy for his new position, vacated with the resignation of Rep. John Conyers Jr. (D-Mich.), on the 13 years he has spent as chairman or ranking Democrat on the panel’s Constitution subcommittee and, more recently, its courts subcommittee.

He also politely reminded Democrats in recent days of his efforts, beginning in the mid-1980s and continuing into last decade, to impede Trump’s efforts to develop portions of New York’s Upper West Side, which Nadler has represented in the New York State Assembly, and subsequently the House, for more than 40 years.

Nadler won a secret ballot 118 to 72, demonstrating that this caucus wants to be ready to clash with Trump if it vaults into the majority after next year’s midterm elections.

“There is nobody better prepared, if the president messes around with the Constitution, to handle it than Jerry Nadler,” Senate Minority Leader Charles E. Schumer (D-N.Y.) said after the vote.

Democrats are openly suggesting President Trump could be impeached. Here's how it would actually happen. (Peter Stevenson/The Washington Post)

Schumer, a confidant of Nadler’s since the 1970s, did not have a vote in the race, but he echoed the sentiment of many House Democrats.

It was not meant as a slight to the importance of immigration, an issue that Nadler’s opponent, Rep. Zoe Lofgren (D-Calif.), had argued was the party’s main focus.

And these internal elections for leadership posts and top committee slots often turn largely on personal relationships that lawmakers build over decades in office. This race was no different.

Nadler had the backing of most, if not all, of New York’s 18 Democratic lawmakers, as well as many members of the Congressional Black Caucus. The CBC has long held that seniority (Nadler was elected in 1992 and Lofgren in 1994) should be the most important factor in these posts, rather than qualities such as the ability to raise money. That’s because many of its members come from poorer, urban districts and do not have the wealthy donor bases of some of their colleagues.

Yet Lofgren hails from a state with 39 Democrats, and with more than 60 women casting ballots in the Democratic leadership races, she was considered a strong challenger for a post that Conyers vacated amid sexual harassment allegations.

One Democratic handicapper familiar with recent internal races expected Nadler to win by about 15 votes. Instead, he won by more than double that margin.

What changed the calculus?

“The constitutional argument,” Rep. Gerald E. Connolly (D-Va.) said in explaining the broad support for Nadler. Democrats, he said, must “prepare for the coming storm.”

House Minority Leader Nancy Pelosi (D-Calif.) played down any division within her caucus, suggesting that the race was spirited but helpful in highlighting key issues. “It was a good, healthy race,” said Pelosi, who stayed neutral. “I thought they both made a very good showing.”

Schumer said he first met Nadler when he “a West Side kid, one of the leaders of the West Side political movement.” The Brooklyn Democrat won his first assembly race in 1974, and Nadler won his two years later.

After a failed 1985 mayoral bid, Nadler won his House seat in 1992 and became a force on the Judiciary Committee, particularly as a top defender in 1998 of President Bill Clinton during his impeachment hearings.

“History and the precedents alike show that impeachment is not a punishment for crimes but a means to protect our constitutional system,” he said then in his opening statement during the committee’s proceedings. “And it was certainly not meant to be a means to punish a president for personal wrongdoing not related to his office.”

A fairly doctrinaire liberal, Nadler represents a district where Trump received just 19 percent of the vote last year. He refused to attend Trump’s inauguration, saying that he was “legally elected” despite allegations of Russian interference. Instead, Nadler said then, Trump’s actions inflaming racial tensions made him “not legitimate” as president.

By May, after the firing of James B. Comey as FBI director, Nadler told CNN that there might be a “very strong case” for obstruction-of-justice charges against Trump.

Democrats are careful to say that Nadler will not push too far or too fast on any impeachment proceedings. “He doesn’t rush to judgment about anything, very deliberative,” said Rep. Joseph Crowley (D-N.Y.), a friend of more than 25 years.

Such cautious statements aside, it’s hard not to conclude that Nadler was given his new job for a singular reason.

“It’s something I think he was made for,” Crowley said. “He’s at the right place at the right time and when we need him most.”

Read more from Paul Kane’s archive, follow him on Twitter or subscribe to his updates on Facebook.