Large countries won't risk going into full-scale nuclear war, the most they would do was send Special Forces into the enemy countries.
Here's an excerpt from an article I was reading about a nuclear war. Blair was a former missilier. According to him, there is a plane flying above the United States this very minute that can launch every nuclear warhead in the United States' arsenal with the push of a button.
"Today, that war plan continues to follow the president -- the commander-in-chief -- wherever he goes. It is found inside a suitcase, better known as the nuclear football.
According to Blair, that suitcase contains several options that would call for massive retaliation.
'Well, the major options are called major attack options and there are basically four of them and any one of them would destroy Russia as a functioning state,' says Blair.
In the spring of 2000, a group of senators began to worry about just that. They went to Blair with a question: Why does the Pentagon feel it needs to keep so many nuclear warheads on combat alert? The answer, Blair told them, can be found by understanding the war plan options that he believes are inside the president's suitcase.
'MAO Four,' says Blair. 'Major Attack Option Number Four. If the president chooses this option, it would unleash at least 2,300 weapons immediately. It would just flatten Russia, [it] would be a radiating ruin for centuries. That's MAO Four. That's a Cold War option that we keep in the nuclear football -- the suitcase at the disposal of the president. And that's what drives our current nuclear operation."
For the full story:
http://www.cnn.com/SPECIALS/2000/democracy/nuclear/stories/nukes/index.html
There are 5 pages, make sure you read them all.