Sepcialist Jeremy Hall v. Department of Defense

This is all over the news today. Although some have been talking about it for a while. Here's the facts:

Jeremy Hall joined the Army for the same reasons anyone does -- a desire to serve his countrymen and his nation, a career advancement opportunity, and to broaden his horizons about the world. He's attained the rank of Specialist, which is the equivalent of a sergeant, and like pretty much everyone else in the military, he was deployed to Iraq. While in Iraq, he served as an MP and got put on a second deployment at a forward operating base. Specialist Hall is an atheist, which was known to his fellow soldiers. From CNN:

Known as "the atheist guy," Hall has been called immoral, a devil worshipper and -- just as severe to some soldiers -- gay, none of which, he says, is true. Hall even drove fellow soldiers to church in Iraq and paused while they prayed before meals.

He worked with the base chaplain and organized a group of atheists, agnostics, freethinkers, and other adherents to non-Christian religions. He posted flyers around the base consistent with the rules the chaplain gave him for doing so. A variety of people, including both military and civilian personnel, attended the meeting. Also in attendance was Major Freddy J. Welborn. Welborn listened at the meeting quietly for about ten minutes.

Then Major Welborn allegedly stood up and told the attendees, and specifically Specialist Hall, that the meeting and the people there were acting contrary to the Constitution, the intent of the Framers (who he claimed were Christians and wanted to create a "Christian nation") and the welfare of both the country and the military, threatened to block Hall's re-enlistment in the Army, and he allegedly threatened to seek criminal charges against Spec. Hall under the UCMJ.

Major Welborn denies having done any these things. No charges have ever been filed against Hall. However, there were no further meetings of the atheist group. Instead, Hall filed a lawsuit against Welborn and the Army for unlawfully promoting a religion under color of law within the ranks of the military.

Let's assume for discussion purposes that Maj. Welborn's denial is untrue, and he did what Spec. Wells says he did. If so, is there any reasonable defense that could possibly be offered against the claim in Hall's lawsuit? It's pretty obvious, at least to me, that Spec. Hall not only has the right to openly serve in the military as an atheist, but that he also has the right to form a group like this without interference from command. I think it's highly important that Welborn delivered these pronouncements while wearing a Major's oak leaf, and that he did so to an enlisted man, which in my mind constitutes interference with Hall's rights from a position far up the chain of command. Perhaps someone else might feel differently about this, and I'd welcome your point of view.