SOUTHBOROUGH — It happened a lifetime ago, in the days when few people knew who Michael Dukakis was, and still fewer could imagine the life that spread out before him — the governorships, the bid for the White House, the career today as an academic eminence grise.

But what he saw that day 50 years ago at the Walter E. Fernald State School in Waltham, where people with developmental disabilities were dismissed by their doctors and warehoused by a society content to keep them out of sight, has never left him.

Its tectonic impact is visible as he sits in the corner of a conference room here at the New England Center for Children.

His familiar strong-and-firm voice grows thin. He speaks haltingly. His eyes fill with tears. He’s clearly choked with emotion by the memory of it all.

“We were in a building with a concrete floor, kind of the size of a small basketball court,’’ he recalled. “There were 75 boys, half of them naked, sitting in their own excrement. The stench was overpowering. They were rocking back and forth for hours. With two attendants. In Massachusetts. Unbelievable.’’

What then-state Representative Dukakis saw in the adult wards later that day was similarly appalling, its visceral impact still apparent.

He said he was still rattled when he returned home to his wife that day in 1965.

“I said to Kitty, ‘You won’t believe what I’ve just seen,’ ’’ he told me. “I became an advocate for the suing parents and basically said, ‘Look, if I get myself elected, we’re going to do something about this.’ ’’

And that’s what he did.

Dukakis was elected governor in 1974. A year later, a small group led by Vincent Strully Jr. started the New England Center for Children at Taunton State Hospital — where similar, medieval conditions existed — with a $30,000 grant from the state.

“He was the governor,’’ said Strully, sitting across the table from Dukakis. “That’s where we got the grant from. We were having a hell of a lot of trouble getting money out of the system. Without a doubt, we don’t exist in today’s form, which is having an impact on thousands of kids with autism around the world, without that first initiative.’’

The fruit of that seed money is apparent at the bright and polished center that sits along a stretch of Route 9 here, where the lives of children from 18 months to 22 years of age are transformed through education, research, and technology.

Walk through the place with Michael and Kitty Dukakis and it’s difficult to imagine that those dark days at Fernald — in the span of history just an eye-blink ago — festered just 23 miles away in Waltham.

Instead, speech and language pathologists tailor special programs to meet individual needs. Motor skills are honed at the Michael S. Dukakis Aquatic Center. Web-based lesson plans guide teachers of 4,600 students from around the world.

“People don’t understand that we’ve come centuries,’’ Dukakis said as we walked through the place recently. “That kid would have been sitting on the floor rocking back and forth years ago.’’

Instead, a young boy named Luke is sitting at the computer, wearing cool headphones and watching a computerized version of the beloved story of Thomas the Tank Engine, the tale of a fictional steam locomotive.

In another classroom, boys and girls are side by side with teachers, striking hopeful chords. “I am brave!’’ they exclaim. “Peace begins with me!’’

Dukakis is a member of the school’s board of directors, one of seven boards on which he serves. He teaches public policy at UCLA in the wintertime and spends the rest of the year at Northeastern, where he is a distinguished professor of political science.

Dukakis is able to teach his students about the hard work, the nuts and bolts, and the political minefields that accompany the confrontation of expensive and nettlesome social issues.

And he knows about the euphoria and searing personal pain that come with electoral wins and losses.

So he doesn’t need to read Hillary Clinton’s memoir to know how she felt when the White House slipped away from her last November.

“Bad. Bad,’’ he said, describing how he felt after his 1988 loss to the first President Bush. “First, you’ve disappointed literally thousands of people who worked for you. I made two very big mistakes in that campaign.

“One was to make the decision — I made it, nobody else — that I would not respond to the Bush attack campaign. You can’t do that. He was so vulnerable in so many ways. I didn’t want the thing to become a pissing contest with two kids in the sandbox throwing sand at each other. And, secondly, as a guy who always won with massive grass-roots campaigning, I spent too much time talking to people who I thought knew more than I did about how to win the presidency.’’

It took Barack Obama’s historic 2008 campaign to validate the premium Dukakis always placed on precinct-by-precinct political warfare.

That’s how Obama won, Dukakis tells his students.

But these days, they have another question for him: How in the world did a man like Donald Trump become the most powerful man in the free world?

“Most of my students in both universities — at least the ones taking my courses — think he’s crazy,’’ Dukakis said of Trump. “But he has in a funny way dramatically increased interest in public service on the part of these students. They now understand that elections matter. This is not Tweedledum and Tweedledee anymore. There are consequences.’’

Dukakis said he wants his students to examine Trump’s campaign, to conduct a postmortem analysis of why so many Americans supported him.

“I think there was a combination of unhappiness on the part of folks who were seeing very little improvement in their lives,’’ he said, “while a slice of America was doing quite well and I’d say maybe the top 20 percent were doing quite well, and the top 2 percent were doing exceedingly well. And then there was this four-year campaign to demonize Hillary Clinton.’’

Time heals. Mostly. But defeat still stings.

“I’m not happy I lost,’’ he said. “You don’t run for that office to lose. And, believe me, if I’d beaten Bush I, you would never have heard of Bush II. That would have made a huge difference. But time’s a healer. You get over it. I love teaching. And I love working with these young people.’’

Dukakis turns 84 in November. When he’s not teaching in Southern California, he walks 2 miles to the Northeastern campus and 2 miles back home each day.

I ask him how long he intends to keep doing it, this classroom work that likely will be the last professional chapter in his long career of public service.

“Until somebody taps me on the shoulder and tells me that I’ve lost it,’’ he said.

Until then, he’s still working on his legacy.

That legacy lives in the students whose papers he’s correcting, whose minds he’s shaping.

And it’s in places like this in Southborough, where the footprints he’s left can be traced back to that awful tableau at Fernald, once the nation’s oldest institution for people with developmental disabilities. It was closed in 2014 and sold to the city of Waltham.

That scene — that smell, that horror — was a defining moment in which a young man faced the unspeakable and resolved to do something about it.

And then did.

Thomas Farragher is a Globe columnist. He can be reached at thomas.farragher@globe.com.