Article V does not and constitutionally could not require the United States to commence war if a NATO member is attacked. For example, if Montenegro were attacked by Serbia. A congressional declaration of war would be necessary to defend a NATO member from aggression under the Declare War Clause of the U.S. Constitution, Article I, section 8, clause 11.
But the law bends to become an instrument of power, not of justice. The plain meanings of words are routinely ignored under the banner of Realpolitik. Article V is exemplary, as a few pages of history and the treaty text demonstrate. Läs artikel