A non-aggression pact is a treaty between two or more governments agreeing to not engage in open warfare against each other. In late 2373, after the Cardassian Union joined the Dominion the Dominion made significant political inroad into the Alpha Quadrant by signing several non-aggression pacts. The Tholians, Miradorns, Bajorans and the Romulan Star Empire were among the governments to sign these treaties. This basically left only the Federation and Klingon Empire to openly oppose the Dominion's actions in the quadrant. (DS9: "In the Cards", "Call to Arms"; The Dominion War Sourcebook: The Fires of Armageddon)