Fifty years ago this week, on Feb. 8, 1964, Rep. Howard W. Smith, a segregationist Democrat from Virginia, stood on the floor of the House to propose an amendment to the Civil Rights Act. Title VII of the bill, which the chamber had been debating for a week, was written to ban employment discrimination because of race, color, religion, and national origin. To the list, Smith added one more category: sex.

The House, which counted just a handful of female members, erupted in laughter. “I am serious,” Smith drawled. “It is indisputable fact that all throughout industry women are discriminated against.”

In that moment Smith helped catalyze the modern feminist movement—even though, or perhaps because, his motives were hardly feminist. Smith’s mischievous intervention has long been told as an amusing footnote, and opponents of expanded women’s rights, especially early on, used it to stymie efforts to expand gender equality in the workplace. But the story deserves more attention, because beneath its surface lie the sort of ironic complexities that often define our political history. The tale of Smith’s amendment is really about the circuitous and unpredictable ways that legislators and activists combine to push society forward.

Smith had previously tried all sorts of tricks to block Title VII from becoming law as the chairman of the Rules Committee, which approves legislation before it gets to the House floor. Adding sex to the bill, he figured, could undermine Title VII by forcing the government to spend time and resources cracking down on discrimination based on gender, and not just race. At the very least, he hoped to cause mayhem among the liberal supporters of the bill, many of whom had an easier time imagining racial equality than gender equality.

Still, the amendment passed, and when President Lyndon Johnson signed the Civil Rights Act on July 2, 1964, it became illegal for employers to discriminate on the basis of sex. It was a moment when women’s rights activists were finally making other gains—most notably with the 1963 Equal Pay Act, which mandated the same wages for the same work and which John Kennedy signed. When Title VII of the proposed act was added a few months later, the activists saw a chance for an even bigger gain. Adding one word—“sex”—to the list of protected classes could revolutionize the workplace. The problem was, no one wanted to introduce the amendment: Even the groups’ allies were afraid it would scare off tentative conservative supporters of the Civil Rights Act, who might support a bill to help minorities, but not women. So the women turned to Smith.

The racism of Howard W. Smith—“Judge” to his colleagues—was well-known: As the head of the Rules Committee, he had let dozens of civil rights bills wither and die. Less well-known was his quiet support for women’s rights. A longtime friend of Alice Paul, co-founder of the National Woman’s Party, Smith had been a regular sponsor of equal rights amendment bills since 1945. So when the women’s groups asked him to introduce the Title VII amendment, he said yes.

Smith first gave notice during the Rules Committee hearings in early January 1964. “I have just received a letter this morning, which I was going to bring to your attention later, from the National Women’s [sic] Party,” he said to Rep. Emanuel Celler of New York, who was testifying as one of the bill’s sponsors. “They want to know why you did not include sex in this bill. Why did you not?”

Never one to pass up a chance at shtick, Celler played along. “It reminds me of the Frenchman who was going up the Empire State Building in New York. Somebody said, ‘How do you like it?’ He said, ‘Well it reminds me of sex.’ ‘Reminds you of sex? Why is that?’ The answer was, “Everything reminds me of sex.’ ”

Smith didn’t laugh. “I have not found out yet why you did not put sex in,” he continued a few minutes later. “I think I will offer an amendment.”

The following month, when Smith made good on his promise, Celler immediately rose in joking opposition. “I can say as a result of 49 years of experience,” he said, “that women, indeed, are not in the minority in my house. I usually have the last two words, and those words are ‘yes, dear.’ ”

More serious opposition came from Edith Green of Oregon, whom the White House had asked to speak against Smith’s amendment. Both Green and the Johnson administration worried that the proposal would make the bill harder to pass. “At the risk of being called an Aunt Jane, if not an Uncle Tom,” she said, “let us not add any amendment that could get in the way of our primary objective.” Despite the opposition, the amendment passed 168–133. When the vote was announced, a woman in the gallery shouted, “We’ve won, we’ve won!” Another yelled, “We made it, God bless America!”

Smith’s motives were complex, to say the least. No doubt he saw the amendment as a tool to gum up the bill, before and after passage. But while it may seem incongruous today, it didn’t seem contradictory to him to be against civil rights and for gender equality. In fact, Smith’s commitment to white supremacy fits neatly with a racist strain of the mid-20th-century women’s movement that gained currency in response to civil rights advances: objecting to giving labor protections to black men, but not white women.

At first, Smith’s amendment drew only widespread ridicule. This is the part of the story you may have heard before. The New York Times editorial board worried that the Rockettes would now be forced to include male dancers. Franklin D. Roosevelt Jr., the chairman of the Equal Employment Opportunity Commission tasked with putting Title VII into practice, considered the provision a joke. When a reporter asked “what about sex?” he replied, “Don’t get me started. I’m all for it.” Roosevelt and a majority of his commissioners had no intention of enforcing the ban. In September 1965 they voted to permit gender discrimination in job advertising.

But the EEOC’s curt dismissal of the sex discrimination ban provided just the sort of immediate, concrete challenge that the burgeoning modern feminist movement needed to generate momentum. Two of the EEOC commissioners, Aileen Hernandez and Richard Graham, dissented from the job-advertising ruling, and the next year joined several dozen people in forming the National Organization for Women. Though NOW’s charter outlined a broad set of goals, its first concern was forcing the EEOC and Congress to take Title VII’s sex discrimination provision seriously. Allies of the movement soon fell in line. The United Auto Workers, among others, said, “We reject out of hand” the idea that the provisions were a fluke. “The point is that Congress did bar employment discrimination on sex grounds, and that bar should be vigorously enforced.”

By the early 1970s, the feminist movement had produced its own lawyers, who honed their skills by pushing courts to enforce Title VII against workplace discrimination. It also developed a powerful lobbying force in Washington, which led to a series of bills that strengthened the Civil Rights Act, including a 1972 law extending it to cover local, state, and federal governments.

Few people today remember Howard W. Smith as anything other than a soldier in the South’s losing war against civil rights. But one could argue that without the EEOC’s initial weakness on sex discrimination—which is to say, without Smith—modern feminism might not have developed the strong institutional structure that has secured many of its legislative successes. “Along with Betty Friedan,” wrote Smith’s biographer, Bruce Dierenfield, “Smith must be credited with giving the modern feminist movement a powerful, if unanticipated, push forward.” Smith was no hero—but then again, sometimes the most effective drivers of progress are the ones who stand strongly against it.