The only reason we still have freedom of speech (well, mostly) is because the courts enforce that part of the Constitution. If the courts didn't do that the politicians would have taken away free speech long ago. If the courts actually enforced the monetary provisions within the Constitution, rather than choosing to "interpret" them into meaninglessness, politicians would not be allowed to create currency not backed by gold (or silver).
The federal government could still borrow under a gold backed currency but its borrowing would be sharply constrained. There would be no Federal Reserve to create money out of thin air with which to buy debt. So real investors would have to be found for the debt, and they would demand higher interest rates. The higher interest rates in turn would constrain the amount of debt that can be issued. (Certainly one reason the government is issuing so much debt today is that the Fed has kept interest rates extraordinarily low. This has kept interest payments tolerable -- for now. If interest rates ever go back up to where they were just a decade or two ago we're fucked.)
As for the argument that if we have a sound currency we'll be outmatched militarily by a country with fiat currency -- I don't think that's really a problem for the U.S. All we need is a couple of aircraft carriers, a bunch of subs, some troops on the borders, and enough nukes to ensure that no one will be dumb enough to nuke us. We could do that with a fraction of our military budget. No one is going to be able to funny money his way to victory over us. Most of our military budget now is for fighting wars in distant lands where we have no business being anyway.