The German Council on Foreign Relations (German: 

Deutsche Gesellschaft für Auswärtige Politik

, DGAP) is a prominent Germany foreign policy research institute and they are concerned about a russian attack:

With its imperial ambitions, Russia represents the greatest and most ­urgent threat to NATO countries. Once intensive fighting will have ended in Ukraine, the regime in Moscow may need as little as six to ten years to reconstitute its armed forces. -

While it isn't clear when "intensive fighting will have ended in Ukraine", let's try with roughly a 10 year period from now.

Resolves YES when Russia intentionally attacks a NATO member. Accidents like a misfired missiles are not sufficient. If it triggers NATO article 5 it is sufficient.