On Sept. 24, 2015, Pope Francis drew ovations from both sides of the aisle in an address to Congress, one of the last joyful bipartisan moments in the Capitol.

Sitting behind the pope, wiping away tears, John A. Boehner (R-Ohio) had his moment of clarity: He would resign as House speaker, announcing it to his colleagues the next morning. He left behind the largest House GOP majority since the Great Depression.

Boehner, who turned 70 Sunday, returned on Tuesday to a very different Capitol, one that had transformed from the heated partisan battles during his nearly five years as speaker into a complete cauldron caught in a constitutional standoff.

On Sept. 24, 2019 — exactly four years after the pope gave Boehner a blessing in private — House Speaker Nancy Pelosi (D-Calif.) stood solemnly before the cameras outside her office to announce the beginning of an official impeachment inquiry against President Trump over his pressure to compel Ukrainian officials to investigate his domestic rivals.

The man who publicly announced his retirement by singing “Zip-a-Dee-Doo-Dah” walked into a Capitol enmeshed in trench warfare, both sides digging in for a protracted constitutional showdown that will last well into the winter.

Officially there to unveil a portrait that will hang in a venerated room just off the House floor, Boehner brought with him one last bid to get his former colleagues to embrace a style that charmed friends and enemies alike. He remains an eternal optimist who views the world as a “glass half full” — usually with red wine in one hand, a Camel cigarette in the other, handkerchief stuffed into his coat pocket to wipe away his ever-flowing tears.

“It doesn’t cost anything to be nice. I’d like to think we were able to disagree without being disagreeable,” Boehner told several hundred well-wishers inside Statuary Hall. “And I’d like to think that we tried to do the right things for the right reasons.”

Boehner rejected the chance to weigh in on impeachment, as he did again Tuesday in an interview with Fox Business Network, where he and one of his lobbying partners, Joseph Crowley (D-N.Y.), the former member of House Democratic leadership, touted a pension plan supported by their firm.

“I’ll just observe,” Boehner said of Trump.

Today’s congressional leaders realized that feel-good moments over the past few years have been reserved for funerals for the likes of former president George H.W. Bush and congressman Elijah E. Cummings (D-Md.), not a living, breathing former leader.

“All the turmoil going on in Washington, John Boehner brought us all back together,” House Minority Leader Kevin McCarthy (R-Calif.), a lieutenant in Boehner’s leadership team for five years, told the crowd.

But Boehner’s message, which struggled to get through to the rabble-rousing Class of 2010 that vaulted conservatives into power, felt even more out of place in today’s Congress.

In Washington four years is akin to the Old Testament’s 40 years — a period of time that doesn’t just form an official presidential term, but also tests institutions like Congress.

It’s enough time for almost an entire generation of newcomers to arrive. Since Boehner left, GOP ranks have shrunk by 50 seats, with nearly 20 more Republicans already announcing they will retire next year.

More than 150 members, about 35 percent of the House, never served with Boehner. The newcomers include hard-charging liberals who called for Trump’s impeachment from their first days in office, and hard-charging conservatives who reject the Boehner ethos — and instead embrace the tear-it-down style of Trump.

Even those Boehner has long known have evolved.

Rep. Devin Nunes (R-Calif.) spent the first half of this decade in Boehner’s inner circle, positioning himself as a go-to quote to trash the right-wing Republicans who formed the House Freedom Caucus.

On Tuesday Nunes did not attend the Boehner parties because he was seated next to Rep. Jim Jordan (R-Ohio), the co-founder of that caucus. Together, the two leading Republicans on the Intelligence Committee worked hand in hand to defend Trump in the day’s impeachment hearings.

Nunes devoted most of his opening and closing statements to trashing the mainstream media that he once so closely courted.

In an expansive 2017 Politico interview, Boehner recalled Jordan as a “legislative terrorist,” for playing a role in helping drive him to retire and then for leading the opposition to McCarthy’s bid to succeed Boehner. Now, McCarthy also works closely with Jordan in their campaign to defend Trump.

Boehner’s closest allies have faded into the background. Some retired a few years ago, such as his closest friend in Congress, Tom Latham (R-Iowa), who now owns a condo in the same Florida resort town as the Boehners. Others lost their reelections, and some are now heading for the hills, such as Rep. Greg Walden (R-Ore.).

Boehner promoted Walden to run the GOP campaign, overseeing the successful 2014 and 2016 elections, after which Boehner’s successor, Paul D. Ryan (R-Wis.), helped escort Walden into the top spot on the powerful Energy and Commerce Committee.

Walden announced last month he will not run for reelection next year.

“So the Boehner coterie is no more, or will be no more by the end of this Congress. And it kind of leaves the field to the firebrands who are maybe more inclined to maybe burn the place down than build up the institution,” said Rep. Gerald E. Connolly (D-Va.), who served while Boehner was minority leader and speaker.

Ryan’s first political campaign, as a student at Miami University in southwestern Ohio, came as a volunteer on Boehner’s first House race in 1990, when the two future speakers first met. Ryan, less than 2½ years after succeeding Boehner, announced he would retire at the end of 2018.

He sat in the second row Tuesday, sporting a beard after spending a few weeks hunting in Wisconsin.

In their tributes Tuesday, congressional leaders described Boehner as a leader from a different era, someone so likable. He started crying during the opening prayer and every speech made jokes about his penchant for weeping at the slightest mention of freedom or poor children.

At a reception afterward, Pelosi led a “Happy Birthday” rendition in a private room and handed Boehner the microphone. There was nothing left to say.

“Hi,” Boehner said.