Sinking Ships

Ships sink.

·        Because of small leaks not repaired.

·        Because huge waves swamp them.

·        Because icebergs rip them apart.

·        Because it takes on too much cargo.

·        Because the captain is incompetent.

·        Because the accumulated rust weakens them beyond help.

·        Because it runs upon a reef.

The USA is a mighty ship.  It seems to be sinking, but why?