Diplomatic action
The Jedi orchestrated neutrality agreement between The Galactic Republic and The Chiss Ascendancy
There's probably never been a Top Secret event that was so widely talked about. Even the name 'Grand Machination' was coined by Republic media. They needed a label for an event they were forced to run stories on; an event which both the Republic and the Chiss first refused to acknowledge, and then later, refused to discuss. Naturally this makes details about the summit exceedingly hard to pin down; however certain details have come to light over time. It is known that at some point early in the year 48 ATC, the Jedi Order approached the Chiss Ascendancy and requested a meeting where a possible neutrality agreement could be negotiated. Reports of varying credibility claim over a dozen Republic operatives were killed either organizing, or protecting the meeting. Additional circumstantial evidence indicates that an unknown number Imperial agents were caught and killed while trying to prevent, identify, or disrupt the negotiations. The Jedi Order has admitted that three Jedi were killed securing the agreement. What is known for certain is that near the end of 48 ATC, the Chiss Ascendancy publicly proclaimed it was seceding from the Sith Empire. This announcement was accompanied by the near simultaneous assassination of three high ranking Sith lords, and two Imperial Admirals. The chaos this generated allowed the Chiss to withdraw with most of an Imperial Fleet. Meanwhile, The Republic abandoned the blockade of the Utegtu Nebula, leaving the Chiss ships a clear path back to their territory. The Republic used the blockade fleet to launch a major offensive at the same time, and The Empire had no choice but allow the Chiss to withdraw back into the unknown territories. There are literally hundreds of theories and stories about how The Grand Machination actually went down, but it is unlikely that the galaxy at large will ever know the details.