I had never heard of it until yesterday. Intrigued I googled it up and came across the NATO website.
Its interesting definition is here. And worth a read to the uninitiated.
http://www.nato.int/docu/review/2014...r/EN/index.htm
We seem completely caught off-guard by Putin's approach. The RAF fighters deployed so far are "tripwires" for a fuller NATO response (apparently).
Thought about this on and off all day, as I work with a very multi national group of people these days - some of the problems of the Ukrainian area are already deeply affecting them.
Hope Merkel is a smart as I think she may be in helping defuse this situation.
No faith in our PM I'm afraid, or our cabinet for that matter.