What is, I think, truly ironic, is that the concept of the Constitution as a "living document" in practice reduces the power of elected representatives, increasing the power of the Wise Old Men/Women interpreting the thing.

The living document justification was - mostly - used to advance social reforms. Some of such reforms, in retrospect, seem to be well timed (if not overdue; such as the end of segregation). What it means, is that democratic mechanisms in America were too slow in reacting to change and had to be replaced by the Platonic "rule of philosophers" (otherwise, the concept of the living Constitution would not have even arised).

However, instead of trying to fix the mechanisms of constitutional updates, liberals advance the undemocratic process by advocating Supreme Court's extendeed powers. I like my Miranda and my equal rights, but I'd like them to come from the legislature (is that too much to ask of my Congressfolk?... err, maybe, look at some of them).