In World War II, there was a very famous poster of a man driving a car with a shadow of Adolph Hitler in the passenger seat.
The caption was "When you ride ALONE you ride with Hitler! Join a Car-Sharing Club TODAY!" This was an appeal to save gasoline for the war effort and that every gallon of gasoline used was one less that could be used to fight the war.
Maher makes the very valid point that it is just as true today as it was during World War II. The reason that American forces are fighting in the Middle East is because there is oil there and the Western nations need it to run their economies. If there was no oil or no need for it, hundreds of billions of dollars could be saved and we could care less what happens there. If even simple, relatively painless fuel economies were enacted, a large amount of that dependence could be eliminated.
He also explains how the Bush administration has made very little effort to have the American people sacrifice things for the "war on terror."