The possibility of nuclear war between America and Russia or China is very low because they understand the consequences of fighting each other.
No.
Russia
There was always the possibility that a nuclear incident could accidentally lead to war between the West and Russia.
There was a great possibility that a (nuclear) war could begin between America and Russia. Or, an incident could happen that could lead to localised conflict based in and around Cuba. When Russia turned their ships, transporting nuclear rockets, away from Cuba and headed back towards Russia, a great relief was felt throughout the West.
Well Détente really relaxed political tensions between the U.S and S.U and the "salt talks" were to limit the arms race so yes between the U.S and Russia Détente reduced the possibility of nuclear war.
Russia or America.
America has roughly 10000 nuclear warheads and russia has anywhere from 5200-8800
America, Russia, France, etc.
No one. The US, Russia, and China each have sufficient nuclear weapons to lay waste to the entire globe.
'Arms race' was the 'race' between America and Soviet Russia to develop as many nuclear weapons as possible.
Yes, russia is the most expected to launch a nuclear attack on America, so America have nuclear missiles aimed at russia, so it can fight back. Defensive wise, i think there are some nuclear bunkers in the desert and important places like the whitehouse. So the answer to your question is yes.
America, Russia, and Korea.