It's a matter of National Security

Please explain to me why the auto industry is so important to our national security that we cannot let it fail?

I understand that our military uses tanks, hummers, and all kinds of automobiles to fight wars. In that regard, I am sure the Government could find a way to pony up just enough money to insure a domestic supply of these vehicles from a smaller automobile industry. But, I am unclear as to why American-made automobiles must be available to the public at large, even if many people do not want to buy them. Is it because in the event of a terrorist attack, we are going to want to get the hell out of wherever is under attack quickly? That didn't work so well in "The Happening" (n.b. don't watch that movie). Or is a more tenuous argument like people need American cars to get to their jobs so they can make money and support our Government through taxes?