How can a country win when it no longer exists? It’s very hard to stop a nuke that’s been launched, and it takes an ICBM a couple hours to arrive after they’ve obviously been launched, at which a point the other guy fires back. Basically both sides of the exchange get hit hard, and have most of their cities and industrial capacity burned down with the people inside. And that’s not even considering a possible nuclear winter, which modeling suggests would last a decade.

This is also why tech to block missiles is controversial. If you open up an even tenuous path to victory for one side the odds of a war starting get much higher.