Things are different now because of nuclear weapons, which means no aggressor can be sure of getting away with any pre-emptive strike. Example: from its very first nuclear test China had announced a “no first use” policy and until today it has, reportedly, less than 300 bombs to serve as deterrent. Now, it’s unlikely that they’d stopped at, say, 250 if that’s not sufficient to deter anyone. Evidently they’re confident that, perhaps, even if only 30 bombs get through any enemy defences, it would be sufficient to make large parts of their targeted nation uninhabitable. Both China and Russia, now designated by the neocons as adversaries, know their own strengths, and if attacked, are likely to retaliate with full force. They probably know they must or they WOULD be wiped out. The neocons too are equally sure of the consequences, and despite their bragging, are unlikely to risk being exterminated themselves (for despite their braggadocio they’re not really courageous people). So all the fear spread by both left and right are unwarranted.