So, US troops have operating on the ground in Syria. (W. J. Hennigan, U.S. special forces kill Islamic State leader in raid in eastern Syria Los Angeles Times 05/16/2015)
It was against The Terrorists, of course. ISIS in this case. Whose side we were supporting in doing that is less than clear.
Henningan reports, "The military's intent was to capture Sayyaf, but he was killed when he 'engaged' U.S. forces, Carter said. The commandos captured Umm Sayyaf, his wife, who the Pentagon suspects is also a member of the Sunni militant group and 'may have been complicit in what appears to have been the enslavement of a young Yezidi woman rescued last night.'"
So it wasn't an assassination mission. And it was helping women's rights. Good to know.