Why did the gun the background check amendment, defeated Wednesday in the U.S. Senate, and eight other amendments to a gun-control bill need 60 votes rather than a simple majority?
The answer is a combination of Senate procedure and the complex politics of guns.
Senators can introduce amendments to existing bills. But, to end debate, on even one amendment, requires 60 votes -- a process known as invoking cloture. Rallying 60 Senators to any cause is very difficult in such a polarized body. Even if cloture is invoked on an amendment, there can be up to 30 hours of debate on it. That's a time-consuming process for one amendment, let alone nine.
Another route is to require 60-votes on the final vote for each amendment rather than to end debate on each measure. Instead of drawing the process out over days or weeks, the votes then can be taken in quick succession.
That's the path Senate Majority Leader Harry Reid (D-Nev.) took. He asked for the Senate's unanimous consent to require 60 votes for each of the nine amendments, and no senators objected.
Why didn't Reid try to get the unanimous consent agreement to set all amendment votes at a 51-vote threshold? Because to do that would have opened the bill up to the likely possibility that amendments favored by gun rights advocates would be added to it.
The Washington Post