An unloaded gun is as much of a threat to someone as a loaded one, if they don't know it's unloaded.
An Islamofascist with a nuke -- any nuke -- suddenly becomes a key player to be negotiated with.
Russia also has a lot of oil as well. If we were smart, we'd help Russia by buying their oil and make 'ol Vlad understand that we're not too happy about them arming our enemies. Make no mistake, I think Vlad wants to resurrect their past greatness by repackaging communism but with himself firmly in charge. You could say that by buying their oil we're extending their lifespan and would allow them to do exactly that. But, if in their death throes they think they have nothing to lose, they will trade their nuclear knowledge, material and warheads for a chance to just postpone the inevitable for a day.
We need to give Vlad the opportunity to save Russia with our help but he has to make a commitment to NOT arm or help our enemies. It might also help if he realizes that our enemies (radical Islam) are his enemies.