According to Mitch McConnell, the U.S. Senate was designed to check hasty legislation, and therefore it's a great idea to require 60 votes to close debate and call a vote. But would the founding fathers have favored this idea?
No. The Constitution states plainly that both Houses of Congress require a simple majority to do business. Certain matters -- treaties, amendments, over-riding Presidential vetoes -- require a two-thirds majority,and these exceptions prove the rule: majorities prevail everywhere else. Initially, both Houses had a rule for calling the "previous question," closing debate by majority vote.
James Madison wrote that in requiring a "super-majority," "the fundamental principle of free government would be reversed. It would be no longer the majority that would rule: the power would be transferred to the minority."
So it was in the beginning, and so it continued in the House of Representatives. But in the Senate, in 1805, Vice President Aaron Burr -- not one of the most sterling founding fathers -- called attention to Senate rules that he considered unnecessary, among them the "previous question" provision. The Senate accommodated him the following year by dropping the rule, but clearly it didn't anticipate unlimited obstruction of voting.
Nevertheless, almost by accident, a powerful weapon became available to those expecting to lose a vote. Rather astoundingly, it was not used until 1837, in a debate over censure of President Andrew Jackson. It was seldom used before the Civil War, and became a frequent threat only in the late nineteenth and twentieth centuries, usually by opponents of civil rights laws.
The term "filibuster," from the Dutch word for free-booter, originally described a marauder who waged irregular warfare on foreign territory. The word was then applied to obstruction of legislative proceedings. But it was still a rare event. When it was used in 1917 to prevent Woodrow Wilson from arming merchant ships, a provision to close debate was adopted -- but it required a two-thirds majority. In 1975 this was reduced to three-fifths, or 60 of the 100 senators.
But it was only toward the end of the century that the filibuster became routine, without the tiresome need to actually keep talking until the majority gave up. It began to be stated as basic fact that bills require 60 votes to pass in the Senate, as though that were enshrined in the Constitution.
But it is not in the Constitution, and could be removed any time the Senate chose to revert to what the founding fathers actually had in mind.