I would bet that there are already nuclear weapons ready to go in some major metro areas. I think Putin will be the one responsible for setting them off.
I believe only one will be detonated so that it doesn't raise suspicions about who was behind it. Terrorists will be blamed - as a way for Putin to misdirect the blame. Russia doesn't need the US for trade. With the US crippled it gives Russia a chance to fill in the vacuum.
When the bomb goes off in New York that will be the "disgusting thing that causes desolation" standing where it shouldn't.
Putin will again rush to express condolences to Bush just as he did on 9-11.
Over a period of a year or two the US will figure out that terrorists didn't set off the bomb.
All good investigators ask CUI BONO - Who Benefits
It will be obvious that Russia will have benefited. The world chaos will justify a third term for Putin whose current two term limit ends March 2008. The CIS will realize that their best options are with Russia and NOT the USA. Russia will form a federation of its former republics. The hegemonic policies of the USA will be repudiated.
When it becomes too obvious that Russia will have gained the most- Russia out of fear will launch an all out first strike attack on the US using nuclear weapons. In one hour the Riches of Babylon the Great (USA) will be devasted.
In that period between the bombing of New York and the final destruction of Babylon the Great Jehovah's Witnesses will exit the USA to live in sack cloth exile with their brothers in faith in South & Central America and perhaps another area of the world.