Recognizing the imminent and evolving threat of cyber attacks to transatlantic security, NATO this month resolved to undertake joint cyber defense measures.  In the Wales Summit Declaration, NATO approved an “Enhanced Cyber Defence Policy” which incorporates cyber attacks into the “core task of collective defence” under Article 5 of the NATO charter.  While the Declaration states that cyber attacks are potentially “as harmful to modern societies as a conventional attack,” it does not define the threshold at which an attack is sufficiently severe for NATO to invoke Article 5, which obligates members to come to another member’s aid.  Instead, NATO will decide whether to initiate a collective response on a case-by-case basis.