The Agreement Party was one of two political parties that dominated the Witenagemot of Kropasar.
In 2371, under the Agreement Party, the Kropaslin applied for membership in the United Federation of Planets. But in 2372, there was an election, and their rivals, the Consensus Party, managed to obtain the majority. The membership process stalled shortly after that, however.
In 2375, after Starfleet Intelligence heard rumors that the Kropaslin had acquired a Breen frigate, the Federation resumed membership negotiations. The Agreement Party, then lead by Thane Bendalion Iamor, knew that if the planet was accepted by the Federation while Consensus was in power, it would serve as a strong validation for Consensus. Feeling they could not allow this to happen, seven thanes in Agreement conspired with Fleet Admiral Alynna Nechayev for the Federation to steal the frigate.
Captain Montgomery Scott was able to use his skill with multitronics to hack into the Kropaslin government computer core and determine where the spacedock holding the Breen frigate was located. A strike team from the USS Catherine Mary subsequently made off with the frigate, and the Federation rejected the Kropaslin membership application.
The loss of validation caused Consensus to lose in the next election, but controversy within Agreement over Iamor's actions meant that they were not able to form a stable government either, and the planet descended into anarchy and chaos shortly thereafter.