The synopsis for Neack's book, The Grand Stratagem:
Since leaving Earth more than a millennium ago, humans have traveled across the expanse of the galaxy. Over half of the galaxy is controlled by several major commonwealths in which humans and nonhumans live in peace. Now because of a warning from an escaped slave, a plot a thousand years in the making that will threaten galactic order has been revealed. The election of a fervently nationalistic leader in a human commonwealth has given the conspirators an opportunity to make their move. Old alliances fall and new ones arise in the face of impending war, and no one can remain neutral.