The Alien Threat

Stephen Hawking thinks we shouldn't try to contact aliens. Drezner calls Hawking simplistic:

Stephen Walt and others assume that the presence of aliens would cause humans to form a natural balancing coalition.   I'm not so sure.  My research into other apocalyptic scenarios suggests that some humans -- that's right, I'm looking at you, Switzerland! -- would bandwagon with the aliens.  Indeed, for all we know, some humans are already trying to welcome their future alien overlords.  Which begs the question --  wouldn't Hawking's isolationist policy allow the quislings to monopolize the galactic message emanating from Earth?