David Petraus is a retired US Army general and former commander of ISAF and CENTCOM. He was also the CIA director under the Obama administration. He said: ”If Russia uses tactical nuclear weapons, probably, the United States and coalition forces would try to destroy Russian conventional troops. But this would of course be a “limited” operation in order not lead to a nuclear war.” National Security Advisor Jake Sullivan said that in the event that Russia uses nuclear weapons against Ukraine, that would have devastating consequences for the Russian side.