US requires 3/4 of states to amend the Constitution. The thinking at the time of the Constitution's drafting is that transient majorities are the customary weapon by which free governments are destroyed.
Yes, and the same people who thought that dearly hoped the Senate would transform into a hereditary aristocracy with life-long terms and the Presidency would become a hereditary monarchy because of the same fears.
I don't think citing that line of thinking (by Hamilton and Adams and the others) says a whole lot. It is, perhaps, ironic, that this line of thought was driven by the belief the British system of government was the best in the world. (Incidentally, during that time period, the 'three branches of government' were considered to be the House, Senate, and Presidency, not the legislative, judicial, and executive.)
