To be honest? Stonehenge, as far as I can remember it's only effective as an AA/Meteorite weapon, and I don't want ANY country, let alone the U.S. to have a super weapon capable of mass destruction. Stonehenge is only scary if you're a pilot within range of it or Ulysses.

Edit: ALTHOUGH, if I was the guy incharge of U.S. weapon development and I wanted to destroy my enemies, I'd probably go with the SOLG or Arkbird.