Just to state a fact. Article 5 of NATO (an attack on one is an attack on all) has only been invoked once, by the US. So why did NATO members send their milit

Just to state a fact. Article 5 of NATO (an attack on one is an attack on all) has only been invoked once, by the US. So why did NATO members send their militaries to Afghanistan? The real reason is that most conflicts never happen. Or are resolved before ending in a full war. Either the US or a European NATO country sending in troops would muddy the conflict so much that the risk of escalation is huge.