https://amgreatness.com/2018/07/26/reforming-nato-is-the-only-way
Donald Trump recently ignited yet another firestorm by hedging when asked whether protecting the newest NATO member, tiny Montenegro, might be worth risking a war.
Of course, the keystone of NATO was always the idea that all members, strong and weak, are in theory equal. A military attack against one member, under Article V of the NATO charter, meant an attack on all members.
Such mutual defense is the essence of collective deterrence. An aggressor backs off when he realizes his intended target has lots of powerful friends willing to defend it.
But what happens when an alliance becomes so large and so diverse that not all of its members still share similar traditions, values, agendas or national security threats?
NATO’s original European members considered themselves kindred neighbors under the nuclear umbrella of the United States.
With the inclusion of West Germany in 1955, NATO’s original mission was altered somewhat. It was no longer tasked just with keeping the United States in and the Soviet Union out, but also with raising Germany up rather than keeping it down.
NATO collective defense was designed to offer breathing space against the superior forces of the Soviet Red Army—until the United States could bring in reinforcements or threaten to use its superior nuclear forces against would-be aggressors.
The alliance worked because the United States accepted that Europe needed American help to deter enemies in order to avoid repeats of the disasters of 1914 and 1939. With the exception of Turkey, the older members of NATO were generally seen as sharing the geographical space of Western Europe.