Treaty of Union
The Treaty of Union is the name given to the 2384 treaty which nullified most rights granted to the Klingon Empire under the 2380 Tripartite Treaty, in reaction to the Klingon attack during the Omega Crisis of 2383.
Relations between Task Force 38, the Raeyan Sector, and the Klingon Empire have only chilled since then, with the Klingons refusing to come to the aid of the Horderlin during the Skareen attack on Union, as well as several minor diplomatic incidents and one major affair in 2384, in which the Excelsior was asked to assist a Klingon colonial vessel in the Delta Quadrant, in the Federation's first "olive branch" offering since the Omega Crisis. The Klingon colonial team lured the Excelsior into a deadly trap, in a perverse attempt to get everyone killed in honorable battle and restore peace with the Empire. When the Excelsior escaped, this plan failed, and Klingon relations have been in a deep freeze ever since.