I have never had problems with the NATO Treaty in the way I did with the EU Treaty because the NATO Treaty does not require a NATO member to do anything. There is no supranational court, fines and enforcement. It is a best endeavours voluntary agreement between its members. As we have seen the club fee is set at 2% of GDP spending on defence but lots of members have not implemented this. In the EU the UK was often forced to enact laws and make payments it disagreed with under force of EU law.
The most famous Nato Article 5 says that an attack on one NATO member is an attack on all. All are requested to respond against the aggressor. There is no mandated minimum response for each, and a member may decline to join a war. When the Falkland Islands were illegally invaded by Argentina the US as the leader of NATO made clear she would not help us fight and win the war. Spain a NATO member was very hostile to us. The Nato Treaty did not cover the Falklands.
Less well known is the all important Article 3 which requires each NATO member to take strong steps to look after their own defence as the UK was expected to do in the Falklands. This Article has not been well respected by some European members of NATO this century. Countries have let their militaries wither , relying on the prop of mutual aid.
The European end of NATO has seen plenty of action by generous numbers of senior officers meeting to co ordinate, wargame , intertwine supply systems and develop mutual dependence. There has been less concentration on building larger and more effective national forces so European NATO has more ability to move large concentrations of force quickly. Too much inter dependence can get in the way and slow things down. The EU now is also complicating things by introducing EU led missions and EU joint procurements.
NATO was planned to handle continued US occupation of Germany alongside the UK, France and Russia post war, with the disarmament of Germany. It then defined its role to defend western Europe against the USSR with Germany as a member. Since the end of the cold war it has sought various missions in the Balkans.
If the US wishes to cut herself off from European conflicts there is nothing in the NATO Treaty to prevent her. In 1914 and 1939 US opinion was strongly against intervening in European wars. The UK fought alone after the fall of France until the Japanese forced the US into the 2 nd WW.
History tells us the UK has to look to our own defences, geared to safeguarding our islands and ensuring greater self reliance in industrial and food production.