The Rise of the 60-Vote Senate
How did the Senate transform into a supermajority legislature? To answer this question, we must have a clear understanding of what filibustering was like before 1960, and why senators abandoned this system. I begin with some definitions and a quick historical survey, and then explain the emergence of the sixty-vote Senate.
Gregory Koger. "The Rise of the 60-Vote Senate" Extensions: A Journal of the Carl Albert Congressional Research and Study Center (2012).
Available at: http://works.bepress.com/gregorykoger/14