Ending Spy Battles

[xdesperado]

What do I need to research to unlock a diplomatic solution to Spy battles?

Current game I'm playing mixed factions Thulun, De Valtos, Cadar...am I out of luck and just have to wait it out?
Searched tech trees but only one I could find was Rychart specific?

[renovate]

There is another treaty to deal with spy battles, but it's nearly at the end of the planetary construction arm of the tech tree.