And everybody's dying to know what the other guy knows. </p><p>Revelations that the U.S. has been monitoring the cellphone calls of up to 35 world leaders, including German Chancellor Angela Merkel, have brought into high relief the open-yet-often-unspoken secret that even close allies keep things from one another ??? and work every angle to find out what is being held back. </p><p>So it is that th