Bing West, a former Pentagon official who has done impressive ground-truth reporting on military action, urges in the Washington Post that the United States not send forward air controllers to work with Iraqi troops. He defends military leaders who recommend against deeper military involvement.
There's a political twist to his argument -- the President Obama is reluctant to support large scale military actions, and attendant casualties and consequences, so we shouldn't start up that escalator. I would counter that the President is wisely seeing the limits to U.S. military capabilities and the public opposition to another major war in the region. But I share West's view that Republican candidates should not pretend that halfway measures can achieve success.
As he says, "Republicans should not be advocating incremental escalation reminiscent of Vietnam."