There’s nothing particularly extraordinary about the content of the 27th Amendment to the Constitution. In full, it stipulates that “No law, varying the compensation for the services of the Senators and Representatives, shall take effect until an election of Representatives shall have intervened.” In other words, members of the United States Congress are not allowed to raise or lower their salaries mid-term. That might seem like a common-sense regulation, but its path to becoming law was anything but conventional. From its original proposal to its ratification in 1992, the 27th languished for 202 years and seven months—longer than any Constitutional amendment in American history. Perhaps even more remarkable, its revival was largely credited to a Texas university student who only became aware of it while researching a school paper.

The story of the “compensation amendment” dates to the first session of Congress in 1789, when James Madison introduced a mid-term pay raise ban as one of several amendments to the Constitution. The Constitutional Convention had previously decided that Congress would set its own pay rate, but Madison and other critics maintained that the rule carried a potential for political misconduct. “There is a seeming impropriety in leaving any set of men without control to put their hand into the public coffers, to take out money to put in their pockets,” he noted during discussion of the issue. Supporters considered the compensation amendment a roundabout method of allowing voters to weigh in on congressional pay hikes, but opponents countered that legislators could be trusted to grant themselves a fair and reasonable salary. Some even argued that lawmakers might reduce their pay to a pittance in an attempt to curry favor with their constituents.

Congress approved Madison’s Constitutional amendments in September 1789, but while 10 of them later became famous as the Bill of Rights, the compensation amendment failed to win ratification by the necessary three-fourths majority of the states. For the next two centuries, it hovered in political limbo, resurfacing only periodically during public outcries about lawmakers’ salaries. In 1873, for example, the Ohio state legislature ratified the amendment to protest a congressional pay hike dubbed the “Salary Grab Act.” A century later in 1977, Wyoming followed suit after Congress gave itself another pay increase. By then, a total of nine states had ratified what would later become the 27th Amendment, but it was still well short of the required 38 state total.

The compensation amendment would likely have become a mere footnote of history if not for a young student named Gregory D. Watson. In 1982, the 20-year-old University of Texas at Austin sophomore happened upon the story of the lost amendment while conducting research for a government class. “This one pertaining to congressional pay raises immediately leaped off the page to me,” he later told the Austin American-Statesman. Sensing that he had unearthed an interesting topic, Watson wrote a term paper asserting that the compensation amendment had no expiration date and could still be added to the Constitution if the required number of states ratified it. Despite his enthusiasm, however, his professor didn’t buy his argument. When he got his paper back, he found he had received a “C” grade.

Disappointed, Watson decided to prove his case in the most extreme way possible: he started a one-man campaign to have the amendment added to the Constitution. Though burdened by a job as an aide to a Texas state legislator, he spent the next several months sending letters to members of the U.S. Congress in the hope of recruiting supporters. He achieved his first breakthrough in 1983 when one of Maine’s senators forwarded his proposal to the state legislature, which promptly ratified the amendment. The following year, the state of Colorado also threw its support behind the measure.

Buoyed by his early successes, Watson spent several thousand dollars of his own money on a new letter-writing campaign to state legislators across the country. Thanks in part to fortunate timing—Congress had been chastised for giving itself multiple pay raises during the 1980s—his cause eventually won wide bipartisan support from politicians and activist groups. Five states ratified the 27th amendment in 1985, and nearly 20 others joined in by the end of the decade. Finally, on May 7, 1992, Michigan became the 38th state to ratify the 27th Amendment. After over 200 years, James Madison’s proposal had crossed the three-fourths finish fine.

Watson—who later described the ratification as the happiest day of his life—told the New York Times that he always knew in his “heart of hearts” that he would succeed. “The American people want a Congress that is honest, that has integrity,” he said at the time. “This Amendment is one vehicle by which some degree of decorum can be restored.”

Even after the 27th Amendment was ratified by three-fourths of the states, there were still many who doubted that it would actually become law. A number of legal scholars argued that the amendment had expired after being shelved for so long, while other critics claimed that existing statutes made it unnecessary. Nevertheless, when the Archivist of the United States reviewed the measure, he concluded that the 27th Amendment had met all the necessary requirements. Following a vote in Congress on May 20, 1992, it officially became the law of the land.

Several other would-be amendments have been proposed since 1992, but to date, the 27th remains the most recent addition to the Constitution. Gregory Watson, meanwhile, has continued to work in the political field. Along with serving on the staff of several Texas lawmakers, he spearheaded a 1995 campaign to persuade the state of Mississippi to belatedly ratify the 13th Amendment abolishing slavery. Watson also received some personal vindication regarding the college assignment that kicked off his quest to resurrect the 27th Amendment. In early 2017, following a request from his former professor, the University of Texas at Austin officially changed his term paper grade from a “C” to an “A.”