And when you think of how Congress has always had a Christian chaplain, I really think the Consitution should be read more strictly as referring to governmental legislation not governmental participation. In other words, it's not wrong to open every legislative session with prayers in the name of Jesus, even though that involves a clear preference for Christianity over other religions, because there are no laws being passed concerning religion. That's the way I look at it.
While I TEND to agree that it is not a violation of the letter of the Establishment Clause I look at it from a position of ethics. If the legislative body is not supposed to be establishing a religion then the prayer is a bit dubious with regards to its purpose.
That being said, I encourage prayer. I encourage our leaders to pray. I just don't think it should be on the agenda.
Where I think you and Yaro are missing each other is simply motivation versus action. I don't think anyone disagrees that MLK used religion to motivate his cause. But his agenda was not a religious one such as some we are seeing today (gay marriage, gay adoption bans, abortion, ID in education, etc).
No smoking signs by gas stations. No religion in the public square. The government should keep us from being engulfed in flames on earth, and that is pretty much it. -- Jon Stewart, The Daily Show