The military's mere existence is protecting our freedom to some degree. If we had no military, other countries would be chomping at the bit to get our resources, and there'd be little bloodshed required to get them.
However, "protecting our freedom" can only be used to justify action in other countries when our freedom is legitimately threatened by those countries. In the case of Afghanistan, at the very least the dismantling of the Taliban was justified given the significant threat they posed to American lives, but the task of nation building we took upon ourselves in both Afghanistan and Iraq is not justifiable, in my opinion. There's too much blood and death involved with if anything a negative impact to national security and little overall improvement in the lives of the people within these countries.
Also, I do believe our actions in Libya were justified. Our light involvement prevented thousands of innocents from slaughter. We're all a part of this world, and at the very least we owe that to our neighbors. That has absolutely nothing to do with American freedom, however.
