Sen. Lamar Alexander of Tennessee — a senator’s senator, a bipartisan dealmaker who still believed that good sense and personal relationships could prevail, even in the era of Donald Trump — said Monday he would not run for reelection in 2020.

It has been a trying two years for a more pragmatic senator less comfortable in the radioactive political confines of today’s Washington. He is also, at 78, simply reaching the age for retirement. To the end, an unflinching optimism — the source of both affection and gentle derision from those who know him — shone through.

“I have gotten up every day thinking that I could help make our state and country a little better,” Alexander said in announcing his retirement, “and gone to bed most nights thinking that I have.”

Lamar Alexander’s last act began last summer and ended in a disappointing failure — a perfect proxy for the erosion of civility and compromise in modern politics. The Tennessee Republican looked like the right person in the right place at the right time. Obamacare repeal was dead. But the more practical Republicans, none more so than Alexander, knew they needed to do something to help the law. Otherwise, they would reap the whirlwind.

On the same July night when John McCain killed repeal with a thumbs down, the health committee chair approached Sen. Patty Murray (D-WA) on the Senate floor and asked her if she would work with him on a narrowly focused plan to stabilize the Affordable Care Act’s insurance marketplaces.

“For eight years and four elections, all we were doing was screaming at each in inchoate rage. To have this first small shoot of green grass in the nuclear fallout area is pretty remarkable,” an aide to Alexander told me last year. “His view is, ‘I’m here, I’m going to make a difference.’”

Alexander and Murray did, for a brief moment, agree to what would have been the first significant bipartisan compromise to shore up the divisive health care law. But Washington doesn’t seem to reward anymore the kind of pragmatism that Lamar Alexander and others in the old guard specialize in.

Trump officials (if not the president himself) worked clandestinely to undermine any plan that would help a law that the administration was working elsewhere to unravel. Republican leaders would waver. Democrats saw the shifting reality on the ground and found the anti-abortion demands made by House Republicans and the White House untenable.

During a February interview in his office, Alexander described trying to find a middle ground on the most polarizing issue of the past decade like this: “It’s wandering in a lot of gunfire is what it is.”

He was right — and his plan didn’t make it out alive.

Yet Alexander was already eyeing the next opportunities for compromise. Even in this polarized age, with moderates retiring and ideologues taking their places, Alexander still carried on in his characteristically Tennessean way.

“I was thinking of the image of two drivers of an old wagon heading west sitting in the front seat with the horses out there. If all they do is argue, they never start moving,” he told me. “If they can agree on something, they start heading somewhere.”

There was no doubt in my mind, after talking with the senator himself and with a dozen people who have known him for decades or who have worked closely with him, that Lamar Alexander believed that. The question is whether it’s still true.

Lamar Alexander in a changing Washington

The people who know him well are keenly aware of how ill-fitted Alexander — a former governor and Cabinet secretary who carries with him the political wisdom of his mentor, former Senate Majority Leader Howard Baker, a renowned pragmatist — might be to these times.

“We are functioning in a time of populist extremism, which is inherently nihilistic,” says Judd Gregg, the former New Hampshire senator who was close to Alexander while they served together. “Lamar is the opposite. He is a governing person. He’s in a difficult position.”

It’s a reality to which Alexander has tried to reconcile himself. He stepped down from his role as the No. 3 in Republican leadership in 2012 in a move his friends say was driven by a desire to step out of the political fray and into a policymaking role as the top Republican on the health and education committee. Elected to the US Senate in 2003, after Fred Thompson retired, he saw the Senate change.

Under President Obama — and a Republican leader in Mitch McConnell who had made opposition to the president his top priority — the demands of leadership clearly grated on Alexander.

“I left the leadership because, with all respect, I felt leadership in a legislative body is more like making sure you’re at the head of a parade that’s already formed. You can’t get too far out in front,” said Alexander, renowned for his metaphors among friends and aides. “Or you’re like John Boehner. You’re just a guy in the woods taking a walk by himself.”

Alexander says he has no regrets about his decision to leave leadership. But he seems clear-eyed about the ways Congress is changing, at the expense of the chair post that he sought. On health care, on taxes, and on immigration and spending bills, party leaders — not the policy wonks — are setting the agenda.

“In the Senate, too much has become centralized in the leadership. Part of that is a function of the media and the world you live in because you have to respond four, five times a day, unlike 50 years ago,” Alexander said. “Fifty-two Republican senators can’t do that as a unit, so to be effective in your political activity, you need a highly centralized leader. That does tend to diminish the influence of the committees, and that’s not healthy for the Senate.”

After spending the better part of six months following Alexander’s efforts to push the health care bill, it’s clear that even if he acutely understands how social media and a 24-hour news cycle are remaking politics, he still holds on to a very old-fashioned idea about how Congress can and should work.

“You can lead just as much and sometimes more not being a part of the elected leadership,” he told me. “I mean, there are three office buildings here, and two of them are named for people who are not part of the elected leadership, Hart and Russell. They never were elected to anything. But they were real leaders in the Senate.”

To understand the incongruity, you have to know how Alexander got into politics.

The education of Lamar Alexander

Born in 1940, Alexander was part of a family with deep East Tennessee roots. His mother was “tough as nails,” and his father — a “brilliant man, smart as could be,” says Lew Conner, a Tennessee lawyer who is old friends of the Alexander family — helped shape the even and unflappable disposition that is the source of admiration and gentle mocking from Alexander’s close friends and colleagues.

Alexander set out for a public life from an early age. He attended Boys State, the American Legion’s student government program for high schoolers, and ended up as the program’s governor. After graduating from Vanderbilt University and New York University law school, he clerked for John Minor Wisdom, a progressive federal appeals judge in the civil rights era. Alexander also editorialized against segregation while he was a student at Vanderbilt.

He got his PhD in politics, as he puts it, under Baker, who represented Tennessee in the Senate for nearly 20 years and eventually became majority leader. Alexander served as Baker’s first legislative assistant. The senator was a fount of folk wisdom. One of Baker’s aphorisms, handed down from his father to Baker and then to Alexander, sticks out the most: “I have one piece of advice for you, Howard. You should always listen to the other fella. He might just be right.”

Alexander ran for governor in 1974 and ultimately failed. “I don’t think it’d be overstating it: He was a bit of a geek and a wonk,” Tom Ingram, a former newspaper reporter who has known Alexander since the 1970s and eventually became his Senate chief of staff, told me. “He was more comfortable with policy than rough-and-tumble politics.”

It was an unlucky time for a Republican’s first campaign — Watergate forced President Richard Nixon to resign that year. When Alexander learned from Trent Lott, the future Senate majority leader who had been his roommate in Washington, that President Gerald Ford was pardoning the disgraced Nixon, he stepped out of the phone booth and turned to Ingram: “Well, we’re done.”

Alexander lost that campaign, 44 percent of the vote to Democrat Ray Blanton’s 55 percent.

In 1978, he wanted to try again. By then it was Blanton who was embroiled in an ethics scandal, his administration accused of exchanging cash payments for clemency.

Alexander decided to walk across the state to gin up his retail politics cred, departing from the porch of the house where his mother had taught kindergarten. He was so meticulous that he brought a piece of railroad chalk to mark his progress each day, stopping at high schools along the way to play music with his makeshift band.

“It took him out of being the textbook candidate, with policy papers, to being the candidate who really found himself engaged with people in their natural places of work and play,” Ingram said. “It was a transformative experience for Lamar.”

It worked too. Just shy of 40 years old, Alexander was elected governor of Tennessee.

The Blanton scandal had gotten so bad that the Democratic-controlled state legislature decided to intervene and swear in Alexander three days early in order to stop the flood of pardons. Faith in the state government was cratering.

Alexander says he still remembers what the Democratic speaker of the state house at the time, Ned McWherter, said when asked what he would do with the new governor. It’s another piece of political wisdom that stuck with him all these years.

“I’m going to help him. Because if he succeeds, the state succeeds,” McWherter said, as Alexander recalls.

“I feel that way about President Obama, with whom I disagreed with philosophically, and President Trump, with whom I disagree stylistically,” he told me in our interview. “You know, if they succeed, the country succeeds. And I want to succeed wherever I can do that.”

Alexander became the top Republican trying to make Obamacare work

In a divided government, when compromise was a necessity, Alexander thrived. But now, under a unified Republican government, he seemed paradoxically hamstrung.

His friends caution against going overboard with the “pragmatist” label. There is no love for Obamacare in Alexander’s office.

“We still believe that Obamacare is horrible, terrible, awful, almost evil policy,” one of his top aides told me. Alexander voted for almost every repeal plan put on the Senate floor but one — repeal without replace — even as the Congressional Budget Office projected upward of 20 million fewer people would have health insurance under the various bills.

But when the repeal dream died, he was the top Republican who wanted to fix the law. It goes back, like a lot of things, to Howard Baker.

“What’s the right thing to do first? Then we’ll figure out the politics. That’s religion for him,” Ingram said. “I think he learned it from Howard. In his office, that was the mantra. You didn’t start with the politics.”

In the Obama years, Alexander had teamed up with Murray to successfully negotiate a new federal education framework to replace No Child Left Behind, which had been embarrassingly left unauthorized for years. Then a year later, he helped shepherd through the 21st Century Cures Act, the most significant overhaul of federal policy on prescription drugs in more than a decade.

“I have always been appreciative of his efforts to reach across the aisle. He is a tough partner to spar with,” Murray told me.

But stabilizing Obamacare was their steepest climb yet. The Alexander-Murray plan was supposed to address a crucial problem with Obamacare: Premiums keep rising — in no small part because Trump had cut off crucial Obamacare payments to health insurers for low-income patients. Health insurers were hiking their rates dramatically and might pull out of the market altogether if the uncertainty fostered by Trump continued.

The health committee held hearings, and Alexander — keenly aware of how Washington works these days — lobbied Trump directly. The plan hit its first hurdle in September, as a compromise was coming together, when Republican leaders decided to pursue one last chance at Obamacare repeal (with Alexander’s support) rather than rescue the law.

Alexander-Murray would have been, for all its policy modesty, a rather remarkable political achievement after eight years of partisan gridlock over Obamacare that culminated in last year’s dramatic debate. If it had happened.

But the senator did know what he was up against, even as he held on dearly to projections from outside groups that the proposal to pump billions of dollars into the insurance markets would lower premiums by up to 40 percent in 2019.

“I’ll be very disappointed if it didn’t get done. It should get done. But this is a hard thing to do. You’re asking the president to support something he said he wouldn’t,” Alexander told me, before the plan finally died in late March. “You’re asking House Republicans to support something they said they wouldn’t. You’re asking Sen. [Chuck] Schumer to support something he said he would and then he said he wouldn’t.”

The death of Alexander-Murray

There was a lot of finger-pointing once the bottom fell out of the health care negotiations and the Obamacare fix didn’t make it into the omnibus spending bill that passed on March 23, the last best chance for passing the health care plan. Alexander himself said that if it didn’t get attached to the spending bill, there was a “zero” percent chance it would ever get done.

Democrats pin the blame on Republican leaders and the White House, who they say undermined the deal and never wanted one anyway; thus the anti-abortion demands that they knew Democrats couldn’t accept. Republicans say Democrats should have known that a Republican Congress would need anti-abortion protections to shore up Obamacare, of all things, and whisper that the party’s leaders actually didn’t want to stabilize the law because it would play to their electoral advantage if another round of premium hikes was announced right before the 2018 elections.

The truth is probably some concoction of all of the above. If you press Alexander’s staff, they’ll acknowledge that House leaders had proved difficult throughout the fall, though they insist Speaker Paul Ryan would have accepted the Obamacare fix if Democrats had agreed to it.

Alexander seemed to even successfully win Trump to his side. The president held a phone call in March with Alexander, his Republican co-sponsors, and Trump’s health secretary, Alex Azar, refereeing a debate about the relative merits and downsides of the proposal, and came out on the side of stabilizing Obamacare. But the idea seemed to be simultaneously undermined by staffers within the White House and the health department who opposed a bipartisan compromise. Just as talks were nearing a climax, the White House’s demands for anti-abortion riders and other poison pills were leaked to the press.

At the same time, the reality on the ground had changed. Restoring the subsidies could actually lead to many Obamacare customers getting a worse deal than they had in 2018, which concerned Democrats and prompted their demands for increased subsidies, a non-starter on the GOP side.

It was, as Alexander vividly put it, like trying to navigate a battlefield. He said as the hopes for an Obamacare fix officially died with a Democratic objection on the Senate floor, that the health care negotiations had been “the most frustrating and disappointing time in my 16 years in the Senate.”

“Building consensus that lasts is really hard work,” the Alexander aide said. “That’s what makes it rewarding, but it can be really frustrating.”

The future for Lamar Alexander — and those like him — in the age of Trump

Around the same time the health care compromise fell apart, Trump announced that he would impose tariffs on steel and aluminum, against the wishes of most of the Republican establishment, including Alexander. He said Trump was well-intentioned but that this was a bad policy.

Alexander had used trade during our interview to explain how he approached his relationship with a president who, in so many ways, is his polar opposite. He had said he wouldn’t go on television and criticize the president if he disagreed with him on an issue; instead, he would grab a few of his colleagues and drive down to the White House for a more personal — and private — intervention.

“It takes a little humility. Part of the humility is recognizing that, you know, I offered myself to be president of the United States, and the people didn’t accept my offer,” he says, referring to his 1996 and 2000 presidential runs. “They took Trump and they didn’t take me.”

“I could either give a running commentary every day on how I disagree with him or I could say, ‘Well, the people elected him. What can we work on together?’” he said.

That is Alexander’s modus operandi.

“The Senate is basically just a laboratory of human nature,” he says. “Success in the Senate is based entirely to begin with on relationships. The place operates by unanimous consent, so relationships are the basic structure of the Senate.”

Alexander has hosted McConnell and Schumer at his cabin in the Smoky Mountains several times over the years. More recently, he invited Murray and two other Democratic senators: Sheldon Whitehouse of Rhode Island and Maggie Hassan of New Hampshire, the most junior member of his committee.

“You have to get 60 votes. I say to my colleagues, it’s very hard to get here. It’s very hard to stay here. So while you’re here, you might as well get something done,” he says. “And to get anything done, that takes 60 votes. And to take 60 votes you have to get people from the other party to agree with you.”

The Alexanderian theory of politics has taken some hits in the past two years, with the failure of the Obamacare fix and the tariffs announcement. But the senator is still betting, despite evidence to the contrary, that his view of history can win out. When we spoke, his eyes lit up when recalling that McConnell had said nothing would pass the Senate in 2018 unless it was bipartisan.

He elaborated as only Lamar Alexander would — and stayed hopeful.

“An old-fashioned view of the Senate might suddenly be back in vogue. Johnny Cash was big in the 1970s, but toward the end of the career he suddenly became very big again,” he told me. “If 2018 is the year of bipartisanship, then maybe the kind of things that I work on will be back.”