The Torment of Tantalus - S1-E11
Corrected entry: After the SG-1 team reach the planet and Daniel goes with Earnest to that room with the DHD lookalike object Earnest gives Daniel his diary which says "Like a United Nations of the stars". Earnest was sent there in 1945 before World War II had ended and thus there was no United Nations, it was still the 'League of Free Countries'.
Correction: This is not true; the United Nations did exist from 1942, with the Declaration by the United Nations. The United Nations was the alliance of nations against the Axis Powers, which we now historically call the Allied Powers (a name never used until historians decided on it to distinguish it from what the UN eventually became in 1946). The connotation, however, is different than it would seem; he's describing it as a grand alliance of the stars, not a peacekeeping organization.