There is no such thing as a “filibuster-proof majority”
In his State of the Union address to Congress last week, President Barack Obama asked the U.S. Senate to amend or abolish its filibuster rules to break the Congressional gridlock. Don’t hold your breath. Neither party wants to change those rules because they always benefit the minority party, and each party will have its turn in that position.
You won’t find filibusters in the U.S. Constitution, but they are constitutional. Article I, Section 5, Clause 2 authorizes the House and Senate to make their own operating rules. Senate rules permit filibusters on the bills it considers. House of Representatives rules do not permit filibusters. The term first appeared in politics in the 1850s.