With the New START Treaty between the U.S. and Russia set to expire Thursday, China has weighed in on suggestions it could join a new pact, arguing it is "not fair" to expect Beijing to sign on given the far smaller size of its nuclear arsenal. The expiration comes 15 years after New START was signed by then-U. S. President Barack Obama and then-Russian President Dmitri Medvedev. For the first time in more than half a century, there will be no limits on the world’s two largest nuclear