The New Nuclear Theory

 For over 70 decades the theory of MAD - Mutual Assured Destruction - has driven safety in a world with nuclear weapons. MAD is this, if Russia or the United States used nuclear weapons, the opposing power could do the same and, essentially, the world ends. Or at the very least ends for these 2 countries. 

This same theory has governed France, UK and China. In fact, development of nuclear submarines that cannot be taken out has made this system even more stable. For India and Pakistan, the same MAD system prevails. For Israel and North Korea, their MAD systems are meant to let their enemies know that easy destruction of their small states would result in the destruction of those countries or major cities.

Therefore tactical weapons, small enough to be used on the battlefield, were are assumed to be useless because they would be the trigger to nuclear war. 

Russia is trying to prove this system is fatally flawed because they can use nucs or the threat of nucs to win a conventional war / invasion with Ukraine. Now that genie is out of the bottle, as they say. If they succeed, there is nothing to stop Russia from taking any non-nuclear territory they want. Or China from annexing Taiwan. Or the United States from annexing Cuba. Or India from annexing Sri Lanka. You get the idea.

And with someone like Putin (and Trump) you have a leader who the world thinks might actually go through with it. And the question becomes, will the United States stand up to stop it. Let's face it, the US is not going to risk destruction over Ukraine. Or Taiwan. And those are just the nations we think about. If Russia or China wanted to take over Mongolia, who would support Mongolia at the risk of a nuclear war.

To counter taking over small states, NATO and the Warsaw Pact where created. An attack on either would bring the full power of the United States or Russia to their aid, including nuclear weapons.

If that breaks down, then the boldest expansionist power wins the day.

I don't know how to fix this if Russia goes all in on Ukraine. The only real factor stopping them now is the fear of nuclear fallout either over Russia - which screws them - or over NATO countries which might trigger retaliation.

And, if it works, there is no reason other powers would not use it as well.