The inexorably racist history of the filibuster
By 
Sarah Binder has an excellent account of how deeply the filibuster is intertwined with the preservation of white supremacy:
Foremost among filibustering senators in the 19th century were the proslavery faction, led by John C. Calhoun of South Carolina, who exploited the Senate’s lax rules of debate to block measures that threatened Southern White landholders’ ability to depend on slave labor.
When Steven Smith and I dug up the history of the filibuster in “Politics or Principle? Filibustering in the U.S. Senate,” we identified 40 filibusters (at least those that left footprints for historians to record) between the first one in 1837 and the creation of the cloture rule in 1917, which enabled the Senate to shut down debate with the support of two-thirds of senators present and voting. Of those 40, at least 10 targeted racial issues — including filibusters over statehood for California and Kansas and, after the Civil War, protecting Southern Blacks’ voting rights.
When Steven Smith and I dug up the history of the filibuster in “Politics or Principle? Filibustering in the U.S. Senate,” we identified 40 filibusters (at least those that left footprints for historians to record) between the first one in 1837 and the creation of the cloture rule in 1917, which enabled the Senate to shut down debate with the support of two-thirds of senators present and voting. Of those 40, at least 10 targeted racial issues — including filibusters over statehood for California and Kansas and, after the Civil War, protecting Southern Blacks’ voting rights.
In doing so, we found that, of measures derailed by filibusters in the 20th century, civil rights measures dominated. Of the 30 measures we identified between 1917 and 1994, exactly half addressed civil rights — including measures to authorize federal investigation and prosecution of lynching, to ban the imposition of poll taxes and to prohibit discrimination on the basis of race in housing sales and rentals.
Keep in mind, the 20th-century filibuster scorched many civil rights measures beyond those that it killed outright. Senators secured passage of several celebrated measures to addressing racial equity — such as the Civil Rights Act of 1964 — after defeating filibusters by segregationist senators. That history is surely why former president Barack Obama last year called the filibuster a “Jim Crow relic.”
Attitudes on race continue to color contemporary Senate filibusters. Just last year, Sen. Rand Paul (R-Ky.) temporarily halted passage of a measure that would make lynching a federal hate crime.
If the filibuster wasn’t informally reserved for thwarting civil rights legislation for much of the 20th century, it would have been killed long ago. A 60-vote supermajority requirement for almost everything is not a stable equilibrium, and has already been eliminated for the advise and consent power. Voting rights legislation would be the perfect vehicle, substantively and symbolically, to kill it once and for all.