The Sirius Treaty was a proposed agreement between the Alliance, Empire, Federation, Marlinist Colonies, Kumo Crew, and various other independent groups to strengthen international cooperation against the Thargoids in the Second Thargoid War and greatly expand the remit of the xenological research organisation Aegis. It was put forward by Prime Minister Edmund Mahon during the Galactic Summit of 3307 at Patterson Enterprise in Sirius. If ratified, the Sirius Treaty would have become the Galactic Summit's crowning achievement. The agreement was left unsigned when the Galactic Summit was cancelled early in response to the Neo-Marlinist Liberation Army's Nine Martyrs attack on starports in nine systems on March 11, 3307.
It was believed that Mahon composed the Sirius Treaty sometime before the Galactic Summit, and he made an unprecedented request to the Alliance Assembly to delay the Alliance prime minister election from February 25, 3307, the same date that the Galactic Summit was scheduled to open, to May 27, 3307 in order to avoid a scheduling conflict and prioritise the treaty's ratification. Political observers commented that the controversy stemming from the delay coupled with the treaty's failure likely had a negative impact on Mahon's reelection campaign, although he still went on to win a second term with a plurality of the vote. Mahon continued pushing for the Sirius Treaty's ratification in September 3307, claiming that if the other signatories could be brought back to the table, it was still possible to implement the treaty and restore Aegis, which at the time had been partially suspended and was under investigation over the disappearance of the Alexandria.
- GalNet: Archon Delaine Gatecrashes the Galactic Summit
- GalNet: Thargoid Conflict Discussed at the Galactic Summit
- GalNet: Galactic Summit Cancelled – NMLA Attacks Superpowers
- GalNet: Superpowers Respond to 'Nine Martyrs' Attack
- GalNet: Alliance Election Delayed due to Galactic Summit
- GalNet: Alliance Election Campaigns Resume
- GalNet: Mahon Wins Alliance Election
- GalNet: Mahon: Sirius Treaty Would Save Aegis