[4] The "elaborate alliance systems" among European powers, "each secured by a network of secret treaties, financial arrangements, and 'military understandings'", are commonly cited as one of the causes of World War I.
[18] Wilson "dissociated the United States from the Allies' earlier secret commitments and sought to abolish them forever once the war had been won".
[19] The Fourteen Points were based on a draft paper prepared by Walter Lippmann and his colleagues on the Inquiry, Isaiah Bowman, Sidney Mezes, and David Hunter Miller.
[20] Lippman's task was "to take the secret treaties, analyze the parts which were tolerable, and separate them from those which we regarded as intolerable, and then develop a position which conceded as much to the Allies as it could, but took away the poison. ...
In December 1935, British Foreign Secretary Samuel Hoare made a secret plan with French Prime Minister Pierre Laval outside of the League of Nations and concluded the Hoare–Laval Pact to give away most of Abyssinia to Italy.
[23] The episode severely damaged the reputation of the League,[23] which showed that it could not serve as an effective channel for the adjudication of international disputes.
[25][26][27] The percentages agreement was a secret pact between Soviet Premier Joseph Stalin and British Prime Minister Winston Churchill during the Fourth Moscow Conference in October 1944 on how to divide various European countries among the leaders' respective spheres of influence.
The agreement was officially made public by Churchill twelve years later in the final volume of his memoir of the Second World War.
[37] Prior to their public release in 2010, the Japanese government had gone so far as convicting journalist Nishiyama Takichi, who tried to expose one treaty, for espionage.
[38] Operation Condor was a secret treaty between the US and five South American nations to coordinate counter-insurgency and "dirty war" against communist rebels and other leftists in Latin America.
The decline of centralized foreign policy institutions, which worked closely with a handful of political leaders, sharply limits the uses of secret treaties.
[16]With private international understandings "virtually eliminated" among democratic states, informal agreements "live on as their closest modern substitutes".
"[40] The traditional rule in favor of secrecy of negotiations is in tension with values of transparency: Anne Peters writes that "the growing significance of multilateral treaties as global ... instruments invites a readjustment of the relative weight accorded to the values of discreteness and confidentiality of diplomatic treaty negotiations ... on one hand, and the interests of third parties and the global public on the other hand.