I think Russia is the most powerfull nuclear country, Russia has 2800 missiles, while America has only 2300

Except you also need to consider the missile defense systems, the type/quality of the missile and also the allies: in a war between Russia and the US chances are the UK, Australia, Canada and other European countries will PROBABLY support America.

(depending on who started the war)

Im sure russia has defensive missile systems and as for support former ussr will support russia

Enough on either side alone to wipe us all out. Or at least make us all dayglo green...