When John Dingell Jr. was a child, he met Franklin Delano Roosevelt, the president who dreamed more than 80 years ago that a groundbreaking Social Security initiative might feature a publicly funded national health-care program. Under pressure from the American Medical Association, FDR and his congressional allies scaled back the initial Social Security proposal. But Dingell kept the dream alive.

Indeed, Dingell, who died Thursday at age 92, lived long enough to see a mass movement arise in support of Medicare for All legislation that is now backed by millions of Americans, by dozens of members of the House and Senate, and by most of the leading contenders for the 2020 Democratic presidential nomination.

Toward the end of his life, Dingell asked US Representative Debbie Dingell, his wife and successor as the Democratic representative from southeast Michigan’s 12th district, to promise to carry the fight forward. When the news of his death was reported, Congressional Progressive Caucus co-chair Pramila Jayapal, the Washington Democrat who has organized a Medicare for All caucus, tweeted: “We’ll make good on that.”

US Representative Ilhan Omar (D-MN) echoed the message, observing that “John Dingell defined statesmanship. Every year, for five decades, Rep. Dingell would introduce a single-payer health care bill in the House. I know that when we finally pass Medicare for All to guarantee health care as a human right, John will be smiling.”

The Dingell name has been linked with the health-care fight since before Medicare even existed. In 1943, Dingell’s father, a congressman from the Detroit area who had played a critical role in enacting the Social Security Act of 1935, joined a pair of New Deal stalwarts from the Senate—New York Senator Robert Wagner and Montana Senator James Murray—to propose the rough outline for a single-payer national health-care system.

Seeking reelection in 1944, Roosevelt proposed an “Economic Bill of Rights” that included both “the right to adequate medical care and the opportunity to achieve and enjoy good health” and “the right to adequate protection from the economic fears of old age, sickness, accident, and unemployment.”

Many hoped that the Dingell-Murray-Wagner bill would frame the underpinnings for that initiative. Its sponsors traveled the country promising to “not give up until the fight is won.” After Roosevelt died at the beginning of his fourth term in 1945, Harry Truman pressed the issue—only to be blocked by the combination of Republican obstruction, red-baiting, and the AMA’s big-spending opposition. But John Dingell Sr. kept introducing his national health-care proposal through the rest of the 1940s and into the 1950s. And after John Dingell Jr. took his late father’s House seat in 1955, he continued to introduce it as “The United States National Health Insurance Act.”

When John Dingell Jr. announced that he would retire from the House in 2014, at the end of his 29th full term, there was much attention to the congressman’s remarkable tenure. Initially elected during President Dwight Eisenhower’s first term, he left as the longest-serving member in the history of the Congress. Michigan political veteran Steve Mitchell suggested that, “With the exception of John Quincy Adams, there’s no one with a longer participation in the affairs of the United States than John Dingell.”

In his retirement, Dingell made a new name for himself as a fierce—and frequently hilarious—practitioner of the Twitter arts, who ripped into Donald Trump—and raged about the failure of congressional Republicans to check and balance the Republican president with aggressive oversight.

Dingell is being remembered now for his tweets. But history will remember him as the great guardian of the New Deal, Fair Deal, and Great Society legacies. His legacy will include his championing of organized labor against flawed trade deals and fight for for the Civil Rights and Voting Rights Acts. As the representative of one of the largest Arab-American communities in the United States, he’ll be remembered for his advocacy of comprehensive and humane immigration reform and his prescient votes against the Iraq War and the Patriot Act.

Mention will be made of Dingell’s opposition to gun-control measures—and of his occasional clashes, as the representative from an auto-making district, with environmentalists. At the same time, his role in shaping the Clean Air, Clean Water, and Endangered Species acts will be remembered. So, too, will his determined advocacy, as a key committee chairman and exceptionally engaged legislator, for scientific research and safe food and drug laws.

But Dingell’s greatest legacy will always be his faithful championship of the health-care reforms that FDR imagined and that his father proposed.

Dingell presided over the House vote that approved Medicare in 1965 and was so instrumental in crafting the Affordable Care Act that, when a critic asked if he had read the bill, Dingell reportedly replied, “Read it? I wrote it.”

The ACA as it was finally enacted—after months of negotiation and compromise—was different from what Dingell initially proposed, and from the bolder strategies that his father had outlined decades earlier. But, like many veteran advocates for health-care reform, Dingell saw the ACA as a vital step—one that moved the country closer to the vision of universal health care he had advanced across six decades.

Even as he referred to the ACA as “the first truly transformative piece of social reform legislation in the twenty-first century,” Dingell admitted that it did not contain “as much [control on insurance firms] as I think we ultimately are going to need.”

But he proudly declared, with the passage of the ACA, that “healthcare is no longer a privilege, it is now a right.”

The struggle to guarantee that right continues. Savvy activists, with unions such as National Nurses United and organizations such as Physicians for a National Health Program and Progressive Democrats of America, argue that it will not be fully realized until the United States adopts a Medicare for All approach that operates on a single-payer model.

John Dingell Jr. agreed. He kept the faith—recognizing that truths that were self-evident in FDR’s time remain self-evident in Alexandria Ocasio-Cortez’s time. It was a faith he inherited. John Dingell Sr., speaking in 1946, decried “a deadly barrage of baseless propaganda” against his initial proposal. But he reminded Americans then, just as his son did across the ensuing decades, that health care is not the privilege of a wealthy few. It is the right of all Americans.