Lots of folks are asking about NATO Article V in the aftermath of the Paris attacks. So, let's run through the basics, FAQ-style.
What is Article V? The heart of the NATO treaty--that an attack upon one is equal to an attack upon all.
Is it automatic? No. NATO representatives have to meet and reach consensus.
What is consensus? Does every member have a veto? Yes/no. While an individual country could block it, the more likely outcome is for less enthusiastic members to choose not to "break silence", which is the NATO term for sticking one's hand up and asking for modifications or refusing to go along.
When has Article V been invoked? Only once before--after 9/11 and that example is most telling as you will see below.
Can Article V be invoked against a non-state actor? Yes. See the 9/11 example. Al Qaeda was the adversary. Article V is much more about declaring that an ally has been attacked than anything else.
Ok, Article V gets invoked and then what? Exactly. There is no automaticity to the declaration of Article V nor is there an automatic policy response in its aftermath.
Sure, but this means that every member has to jump in and help, right? No, the Dave and Steve book is all about this reality--that Article V includes the language: "as each country deems necessary."
So, what did NATO do after 9/11? The Bush Administration and especially Rumsfeld did not want NATO help in taking down the Taliban to get after Al Qaeda. However, NATO did send the one asset it has (NATO operations are done almost entirely by the stuff that countries provide for that operation): AWACS planes. Those are the planes with the big disks on top that help to control airspace. And that they did over American cities during the Super Bowl, World Series, New Year's Eve in the immediate aftermath of 9/11. Not every NATO member joined this effort.
What is the point, if it does not mean an immediate military response? Political solidarity has meaning. Since Article V is invoked so infrequently, its invocation has heft. Also, it then means that NATO assets (AWACS and a few others now) can be used and NATO headquarters in various spots can coordinate what countries want to do. The other way in which it matters is that it makes it easier for other countries to join the anti-ISIS effort. Some countries need more multilateral cover when joining an operation--either a UN resolution or a NATO declaration.
Why wouldn't France ask NATO to invoke Article V? France has a long, ambivalent history with NATO. De Gaulle pulled France out of the operational chain of command, and Sarkozy only recently embraced NATO. Any French President has to weigh the advantages that come with its invocation with the potential signal sent that France cannot handle the crisis on its own, that France is not a great power that can operate unilaterally.
What other questions are people asking about Article V/NATO and this event? I can add to this list if people ask questions.