A decision tree for Biden if Putin goes nuclear

This in turn would force countries that have forsaken nuclear weapons in the name of non-proliferation or disarmament — as Ukraine did in the 1990s — to build their own arsenals. Arms control would be dead. Nuclear warfare, by design or accident, would become more likely in more places, from West to South and East Asia. What, then, should US President Joe Biden do? He must deter Putin, obviously, while simultaneously preparing a response if Putin does escalate. But these are two aspects of the same decision: The implied response also does the deterring. Matthew Kroenig at the Atlantic Council,…