A surprise nuclear attack

The military idea

Basically it is to devastate the opposing nation as a whole by employing overwhelming force, with out warning; on civilians, politicians and military indiscriminately. This is not the same as a pre-emptive strike which uses the counter-force method and tries to avoid civilian targets in favor of military and political ones.

Counter measures

A secondary strike could be launched from ballistic missile submarines, surviving land base missiles and already airborne bombers.

Anti-ICBM missiles like the Soviet (A-35 anti-ballistic missile system) and the United States (LIM-49 Nike Zeus missile system) were heavily limited under the 1972 Anti-Ballistic Missile (ABM) Treaty so as only give enough to defeat terrorists, rogue commanders who acted alone or what we now call rogue states.

The Mutually Assured Destruction theory was the ultimate in insane logic and nuclear deterrents!

Lunching rules

The following nations would not use atomic arms unless in revenge for being nuked them selves.

China.
India.
USSR. (Andropov was so paranoid he would have done a surprise attack from his hospice bed. Assuming the A-bombs had not worked then he would have probably even resorted to flinging his zimmer frame at us!)

The following nations would not use them unless there invaded by a massive force from or nuked by a nation.

Russia. (In recent years Vladimir Putin has indicated he wants a surprise attack or at least a pre-emptive strike plan).
France.
United States. (Most of the Cold War was de facto set at doing surprise attack; but Harry S. Truman, Ike, JFK and Ronald Reagan personally opposed this policy and kept the hawks in their place. George W. Bush added the right to nuke in revenge for being attacked with chemical, nuclear or biological weapons).
N. Korea