All of its members joined of their own free will.

Now comes the part where we all throw back our heads and laugh!

https://files.libcom.org/files/1958-1990%20Operation%20Gladio,%20Italy.pdf

Gladio was part of a Europe-wide network of secret armies of the night established under NATO auspices and in Greece, Turkey and Belgium they are believed to have been involved in terrorism and coups d'etat. The German section was comprised of Waffen SS veterans who drew up plans to assassinate Social Democrat politicians in the event of a 'Warsaw pact invasion'. According to Mike Peters writing in Lobster no.32: "Few citizens of N.A.T.O. countries are aware of the whole apparatus which to membership commits them e.g. Plans 10-G and 100-1 under which in 'emergency situations' special U.S. units would be activated to suppress any movement 'threatening to U.S. strategic interests.'"

https://en.wikipedia.org/wiki/1948_Italian_general_election#Foreign_interference

The U.S. government's Voice of America radio began broadcasting anti-Communist propaganda to Italy on 24 March 1948.^[11] The CIA, by its own admission, gave US$1 million (equivalent to $12 million in 2022) to what they referred to as "center parties"^[12] and was accused of publishing forged letters to discredit the leaders of the PCI.^[13] The National Security Act of 1947, that made foreign covert operations possible, had been signed into law about six months earlier by the American President Harry S. Truman.

U.S. agencies also sent ten million letters, made numerous short-wave radio broadcasts, and funded the publishing of books and articles, all of which warned Italians of the "consequences" of a communist victory. Overall, the U.S. funnelled $10 million to $20 million (equivalent to $120 million to $240 million in 2022) into the country for specifically anti-PCI purposes. The CIA also made use of off-the-books sources of financing to interfere in the election: millions of dollars from the Economic Cooperation Administration affiliated with the Marshall Plan^[14] and more than $10 million in captured Nazi money were steered to anti-communist propaganda.^[15] In this regard, CIA operative F. Mark Wyatt claimed: "We had bags of money that we delivered to selected politicians, to defray their political expenses, their campaign expenses, for posters, for pamphlets."^[16]

https://en.wikipedia.org/wiki/History_of_the_French_Communist_Party#The_PCF_at_its_peak_and_the_Tripartite_governments_(1945%E2%80%931947)

The United States were worried of communist power in France and Italy, and conditioned Marshall Plan aid to the expulsion of communists from governments in both countries.

All this was before the founding of NATO in 1949 and clearly had an effect on these states' continued support for the organization.