Use of Article 5 marks policy shift for Europe

Major feature. When Nato agreed 13 September 2001 to invoke Article 5 of the alliance's treaty, under which members agree that an armed attack against one of them is considered an attack against them all, it marked a fundamental shift for European members. But whether or not the US asks its allies for military assistance, the new interpretation of Article 5 is likely to have a profound impact on how Europeans deal with terrorism.