Is the United States alluded to in biblical prophecy? If so, where? If not, why not?

Some people try to say it is. The most recent one I heard was that in Daniel 7, the nation represented by a winged lion is England (for obvious reasons - look at their national symbol) and the United States is the nation represented by the leopard. (One reason being that the leopard is representative of a melting pot - all nationalities melded together.) I'm not saying it couldn't be true, but I don't buy it. There is nothing in the rest of the Bible to verify that interpretation, which leaves it up to individual speculation. If the Bible doesn't flat out interpret it for us, we're better off admitting that we don't know.