In 1947, the year Joe Manchin was born, the US Senate killed voting-rights legislation – again. The “gravedigger,” liberal Democrats complained, was filibuster rules empowering its opponents. Today, as 74-year-old Manchin serves his second Senate term, the chamber stands poised to bury his voting rights proposal the same way. But this time there’s a twist: The West Virginia Democrat, by continuing to support the filibuster, himself serves as sponsor and gravedigger alike. That incongruity keeps alive a continuing closed-door effort by fellow Democrats and the White House to change Manchin’s mind on the filibuster. Even those involved concede it’s a long shot. But they haven’t given up. They confront a familiar conflict over the Senate’s role in the American system. Political minorities embrace the filibuster – which now requires a 60-vote supermajority to cut off debate – as a shield protecting their rights; majorities chafe at the obstacle it presents to action on national priorities. Repeatedly, that conflict has surfaced over attempts to safeguard the vote, among other civil rights protections. As the civil rights movement intensified after World War II, pro-segregation Southern senators made the filibuster their bulwark against proposals to ban “poll taxes” that impeded voting by Blacks. For two decades beginning in the 1950s, frustrated liberals pressed for rules changes to weaken the filibuster. In 1957, the year Manchin turned 10, their ideas revolved around permitting a majority of senators to end debate after 15 days. Majority Leader Lyndon Johnson, as biographer Robert Caro recounted in “Master of the Senate,” flatly rejected them. Today, Majority Leader Chuck Schumer and nearly the entire Democratic caucus support rules changes. They’ve floated several options that could take effect if every Democrat supported them. RELATED: Biden says he supports filibuster carve-out for voting rights One would create a specific filibuster exemption for Manchin’s bill, which would make Election Day a holiday and establish minimum national standards for mail-in ballots and early voting. A second would create a broader but undefined exemption for bills designed to protect democracy – a suddenly salient topic after last year’s deadly January 6 insurrection. A third option, which enjoys the most support among Democratic senators, would make filibusters harder to mount and easier to end. Instead of initiating a filibuster by simple declaration, and forcing proponents of action to overcome it, it would require filibustering senators to talk continuously, as popularized by Jimmy Stewart in the 1939 movie “Mr. Smith Goes to Washington.” It would guarantee that the minority could offer a specified number of amendments to the legislation at issue. It would let every senator speak on the floor twice. But it would ultimately allow the majority to end debate and force final action with 51 votes, not 60. Along with Sen. Kyrsten Sinema of Arizona, Manchin continues to publicly hold the line against steps to weaken the filibuster, much less abolish it. They insist filibusters force Senate majorities to seek bipartisan consensus rather than simply steamroll opponents. But Manchin’s inability to attract Republican support for his voting rights bill underscores how, more typically, the filibuster halts action on contentious issues altogether. That’s why his Democratic colleagues keep trying. “You have a consensus among Senate Democrats that our democracy is at risk, and that does create an opportunity for reform,” said Sen. Chris Van Hollen of Maryland, one of those involved. “The verdict is still out.” Their goal, propelled in part by the upcoming Martin Luther King Jr. Day holiday, is to bring the matter to a head in January. Manchin’s bill represents the most important step Democrats could take to counter moves by Republican-controlled state legislatures to curb voting procedures and tilt election administration in their favor in the wake of former President Donald Trump’s 2020 defeat. “I think it’s a 30-40% chance that we’ll get something significant,” said Norm Ornstein, a congressional scholar at the American Enterprise Institute. As it happens, those Democratic liberals in 1957 ended up winning limited voting rights protections without changing the filibuster. That’s because Johnson, straddling his alliance with fellow Southerners and his ambition to win national favor for a later presidential run, engineered passage of a modest civil rights bill. Later, as president, Johnson pushed through the landmark Voting Rights Act of 1965. Two months after voting rights marchers in Selma, Alabama, endured attacks from local law enforcement on “Bloody Sunday,” he and Senate allies overcame a Southern filibuster by rallying a bipartisan group of 70 senators to end debate. It took another decade before the Senate made filibusters easier to stop. In 1975, a majority of senators voted to reduce the threshold for ending debate from two-thirds to three-fifths, or 60 senators. Among those who backed the change: Democratic Sen. Robert Byrd of West Virginia, one of Manchin’s political heroes.