Its not the cost of a war, it is the reasons it is fought. Lincoln was defending the idea of a nation of united states, and he was a republican (the liberal party of his time) who had just driven out the wigs (the conservatives of their time). He had progressive ideas that eventually led to the emancipation of slaves. To be honest, I would have fought in that one (there are a few others). But to kill Americans over some stupid economic experiment to see if Milton Friedman's Chicago School of economics could actually work is (if you ask me) criminal.