Bush is blamed for pulling out of the And-Ballistic Missile Treaty and deciding to go ahead with the Nuclear Missile Defense.

I am no expert on this, but from a cursory reading of the material, it seems that this was already on the cards under Clinton. There were sharp disagreements between Clinton and Putin and there were detailed proposals to scrap the ABM and go ahead with the NMD. Indeed, it seems that funding for the program was higher under Clinton than Bush.

See this site for interesting details as well as budgetary allocations that actually seem to have dropped under Bush.

Also, Russia is developing a new generation of nuclear missiles that will not be stoppable by the NMD.

Closer to the end of the species?