Comment by chemotaxis

> You cross us? We nuke you.

It's a nice theory, but it works only if every act of war is clearly an act of total war and there's a responsible party to nuke. Who were we supposed to nuke after 9/11? Who do we nuke if the next big North Korean hack takes out Microsoft instead of Sony? Or if it disrupts the US power grid for a week? Who do we nuke if Russia props up the regime in Iran and Iran props up a terror group that attacks our close ally?

That's the thing: nuclear wars appear to have a good track record of preventing conventional war in the mold of "we show up at your border with tanks". But it doesn't prevent the kinds of conflicts in which nuking another country might not be a defensible reaction.