WASHINGTON (CNN) – When Al Franken is officially sworn in Tuesday as the junior senator from Minnesota, he will become the 60th Democratic member of the U.S. Senate and, in theory, give his party its first filibuster-proof majority in more than 30 years.
The last time any party had a filibuster-proof majority in the U.S. Senate was during the 95th Congress from 1977 to 1979, when Democrats held 62 seats. The Senate's filibuster rule had just changed two years earlier, when the threshold needed to invoke cloture, or to end debate, was lowered from a two-thirds majority of senators present and voting to three-fifths of the total senate membership, which translates to 60 votes of the 100-member body. At the time of the rule change in 1975, the Democratic caucus had 61 votes.
However, reaching the 60-member mark with Franken's swearing-in does not automatically guarantee Democrats the ability to end GOP-driven filibusters.
Party leaders must still work to hold the Democratic caucus together on important votes, which could prove difficult with a party that includes conservative Ben Nelson of Nebraska and recent Republican convert Arlen Specter of Pennsylvania on the right and liberal stalwarts like Ted Kennedy of Massachusetts on the left. The caucus also includes two independent senators: Joe Lieberman of Connecticut, who campaigned and voted for GOP presidential nominee John McCain in 2008, and Bernie Sanders of Vermont, a self-described socialist. In addition, both Specter and Franken have said publicly that they would not necessarily be an automatic 60th vote for the party.
Donald Ritchie, associate historian at the U.S. Senate Historical Office, notes that a theoretical filibuster-proof majority did not necessarily translate into smooth legislative sailing for Democrats in the 1970s. During the 95th Congress, even though Democrats had 62 members in the Senate, straight party-line votes were very rare, and filibusters still occurred, comprised of coalitions between Democrats and Republicans. Ritchie says that, at the time, cloture motions to end filibusters often were brought forth jointly by both the leadership of both parties.