Nuclear Deference  How Obama can convince Moscow he's not out to
ruin Russia.   Another issue is regional security. Next year's
U.S. withdrawal from Afghanistan is ushering in a number of
uncertainties in Central and South Asia. In post-American
Afghanistan, the Taliban are likely to increase their influence,
even as Pakistan and India will compete even more intensely
there. Russia's defense policy these days focuses more and more
on contingencies along its southern borders, primarily in
Central Asia and the Caucasus. Moscow has been trying, with
mixed results, to revamp and strengthen the very loose post-
Soviet Collective Security Treaty Organization, which it leads,
to deal with emergencies in that part of the world. A Eurasian
economic union might help, but, to be successful, it will need
to stay economic and voluntary. Americans should lose no sleep
over it: Moscow's desire, and ability, to impose its will on
these partners is small. The Russian empire will continue to
rest in peace.     To many U.S. obse