For the last decade, Harry Reid has been a bulwark against efforts by Republicans and members of his own party to send the core of the New Deal achievement down the road to oblivion. Other Democratic lawmakers may be equally committed, but almost none have the same close emotional ties that he possesses to the Rooseveltian state.

When Senate minority leader Harry Reid announced last week that he won’t run for reelection in 2016, the first thing that flashed through my mind was his age: he’s 75. Only nine senators are older than Reid, and only two of them are Democrats. That underscores how few people still serving in the Senate were born during the New Deal, the period that formed the modern US government, with its social protections, administrative apparatus, and (not so happily) military-industrial complex. For the past 35 years, roughly corresponding to Reid’s career in electoral office, the legislation that Washington enacted during the Great Depression has been a war zone, constantly under attack from Republicans and center-right Democrats.

Reid’s career has been defined by the effort to protect and extend the New Deal legacy. He grew up desperately poor in a Nevada mining town called Searchlight, and his family experienced first-hand the difference that Roosevelt’s accomplishments made in their lives. As Nicholas Lemann wrote in an excellent 2010 New Yorker profile,

He likes to say that his parents’ religion was Franklin D. Roosevelt; practically the only good thing that ever happened in the life of his father was joining a union. “The American government is the greatest force for good in the history of mankind”; Social Security is “the greatest social program since the fishes and loaves.” Sig Rogich, a Nevada adman who worked in George H. W. Bush’s White House, and who, like most establishment Republicans in Nevada, is backing Reid over Sharron Angle, told me that during many evenings at his house he and Reid have relaxed to old Woody Guthrie songs on the CD player—“poignant songs about society and the poor.”

That last bit may be sentimentalized, but Reid seems to have not forgotten, as many younger Democratic politicians have, how class differences define politics—as they must.

“I have made no secret of my antipathy toward the second President Bush,” he wrote. He added that Bush “is an ideologue who has done incalculable damage to the government, reputation, and moral standing of the United States of America.” He twice publicly called Bush a liar, explaining, “When one lies, one is a liar.” Late in his presidency, Bush summoned Reid to the White House and tried to appease him. “I never went to Kennebunkport as a kid,” Reid recalls. “I never went anywhere. And I’ve got no blue blood in my veins, just some desert sand. So as he and I sat there in the Oval Office, I said little in return.”

In the small world of political Washington, it’s extremely unfashionable to say such things without swiftly taking them back (far-right Republicans often get a pass, since, the conventional wisdom has it, there’s nothing to be done about them), so Reid, a former boxer, is often characterized as gaffe-prone. Except that he generally means what he says. To me, one of his finest rhetorical moments came in 2005, at the height of Alan Greenspan’s cult of personality, after the Federal Reserve chair, who had punched President Bush’s ticket when he sought support for his mammoth 2001 tax cuts, testified before Congress about the need to cut Social Security and Medicare:

“I’m not a big Greenspan fan—Alan Greenspan fan. I voted against him the last two times. I think he’s one of the biggest political hacks we have in Washington.”

Likewise, when he called Bush a “loser” and a “liar” and referred to him sarcastically as “King George,” Reid only apologized for the “liar” part. Only not really, because he was referring to Bush’s sudden, about-face decision to store nuclear waste at Yucca Mountain—only 100 miles from Las Vegas and its 500,000-plus residents. “You sold out on this,” he told the president.

To be clear, I’ve disagreed with Reid on plenty of matters, particularly the ingrained liberal-hawkishness that prompts him to support (for example) enlargement and expansion of NATO’s dangerous commitments in Eastern Europe. His rubber-stamping of the PATRIOT Act and his continued support of the drug wars make him party to some of the worst calamities of our time. And I believe that for the best parts of the New Deal to survive, America needs to become more radically democratic (note the small “d”) than it’s ever been. Where Reid has had the biggest impact, however—where he has been indispensable, at times—is in the long-running war on entitlements. When he became Senate minority leader after the Republicans’ triumphant showing in the 2004 elections, he enforced a new discipline among his Democratic delegation.

For the first time since the “Republican Revolution” 10 years earlier, the Democrats began to act like a proper opposition party, taking firm stands against egregious GOP initiatives rather than searching desperately for ways to be “bipartisan.” Under the direction of his consigliere, Karl Rove, Social Security was to be the big domestic issue of Bush’s second administration, with the goal to cut the program for future retirees and reroute part of workers’ payroll tax contributions to Wall Street via personal investment accounts.

Taking a page from the Republicans’ successful opposition to Clintoncare in 1993, Reid and House minority leader Nancy Pelosi, his exact contemporary and the daughter of a New Deal House member, decided that the Democrats wouldn’t offer an alternative to Bush’s Social Security plan, or negotiate on the basis of any of Bush’s key demands. Reid set up a “war room” in the Capitol to coordinate the Democrats’ strategy and worked closely with a coalition of unions and grassroots progressive groups mobilizing against privatization—just the sort of allies who center-right Democrats tried to distance themselves from.

The strategy worked. Bush’s (and his party’s) popularity dropped steadily as he continued to campaign for Social Security “reform.” That, plus the floundering US occupation of Iraq, cost the Republicans control of Congress in 2006. (For more on Bush’s failed Social Security blitz, see my book, The People’s Pension). That led directly to Barak Obama’s election as president in 2008, and—among other things—passage of the 2010 Affordable Care Act, the most important expansion of the New Deal/Great Society state in almost 40 years.

Of course, the ACA was a deeply flawed bill, and it suffered, predictably, from a misguided decision by the Democrats to waste time negotiating with Republicans who clearly had no intention of making health care restructuring a genuine bipartisan effort. But the White House bears far more responsibility for that decision than either Reid or Pelosi, and so for the Democratic debacle in the 2010 elections. The same can be said of the decision to expose Social Security and Medicare to the misguided “reforms” of Alan Simpson and Erskine Bowles, the co-chairs of the National Commission on Fiscal Responsibility and Reform.

In raw political terms, the greatest sin of the Obama administration has been to forget the lessons that Reid taught in the years leading up to Obama’s election. In one crucial fight after another, the White House chose to negotiate directly with congressional Republican leaders, following their ground rules and leaving lawmakers from his own party on the sidelines.

The Democratic route in November 2014 appears to have brought the lessons of the earlier Reid era back into fashion, at least for a time. In January, four Democratic filibusters killed a Republican effort to gut the president’s executive orders protecting some 5 million undocumented immigrants from deportation. Reid has held his forces together on a succession of votes, reinforcing Obama’s veto threats on such matters as the recent bill to block new rules that would speed up union elections. Arguably, by following Reid’s lead and swearing off bipartisanship, Obama is salvaging the last two years of his presidency, just as Bill Clinton left office with high ratings after repeatedly squashing the Republican-controlled Congress’s efforts to pass a mammoth, upper-income tax cut. Of course, there’s always time for him to backslide.

Reid’s approach can be learned, but it helps greatly that he was born with an understanding that electoral politics are marked indelibly by the war between the haves and the have-nots. The experience of the Great Depression, and the lessons it passed on, haven’t gone away. Through Reid especially, they’ve had a deep impact on the federal politics especially of the past two decades, on matters extending from the budget to social services to employment and immigration—in other words, on everything that concerns working households.

Curiously, that claim is difficult to make for the generation of Democratic lawmakers who followed the Great Society period of the ’60s. These were the first cohort of “New Democrats,” eager to distance themselves from the more openly class-based politics of earlier decades. Perhaps the fact that they grew up in a period of unprecedented prosperity had something to do with this. It would be sad to think that only another Great Depression could produce another cohort with Reid’s consciousness. But perhaps the Great Recession will do the trick.