Regardless of the hows and whys we are currently involved in a war.
You can argue about the causes all you want (if so, please start another thread) but at the end of the day, we'll still be over there and will have spent hundred of millions of dollars more.
"We the people of the United States, in order to form a more perfect union, establish justice, insure domestic tranquility, provide for the common defense, promote the general welfare, and secure the blessings of liberty to ourselves and our posterity, do ordain and establish this Constitution for the United States of America."
I see something in there on providing for the common defense, but nothing on promoting the general welfare of residents of foreign countries.

