The AMT has been around since the 70`s. Not, ``near the end of the dem controlled congress`` It was meant to insure that folks with high incomes paid taxes.

http://en.wikipedia.org/wiki/Alternative_minimum_tax

The income levels have not been adjusted since then and the AMT is now affecting upper middle income families more and more, especially those with kids. Please note that Congress has been Republican controlled since 1994 has ignored AMT reform in favor of tax cuts for the super wealthy. (Like Biajj is now, and congrats to him :) )