Unfortunately, to Liberals, Pacifists, America-Haters and Appeasers (Which pretty much encompasses the entire left side of the political spectrum) there is no reason to fight...ever. Which explains why they are always cutting military spending.
They think the job of the President is to safeguard the lives of our military. Conservatives generally understand that the job of the military is to safeguard the lives of our citizens as a tool of national policy.