zlacker

What I've noticed is that we have nearly thirty of them, and two of them were passed in my lifetime.

>>stonog+(OP)
The timeline looks like this:

http://www.paufler.net/brettrants/161_amendments_graphs.html

I wouldn't consider that indicative of the ease of passing an amendment. Perhaps you do. It appears to require an increasingly-hard-to-get combination of (1) widespread agreement that a problem requiring an amendment exists and (2) widespread agreement on what the nature of the amendment should be.