Defining "establishment"

I am so pleased and honored by Fr. Araujo's decision to join us at the Mirror of Justice.  And, I appreciate very much his call for an "answer" -- or something closer to an answer than what we have at present -- to the question, what is an "establishment" of religion for purposes of the First Amendment?  He writes:

My quest, and I suspect that of many others interested in the First Amendment, is for a solid (not “simple”) answer that will be a strong, reliable, and enduring guide for lawyers and judges who tackle First Amendment concerns. I believe that lawyers and judges of today can provide this answer that takes into account the concrete problems that the Founders were trying to address and not the imagined fears of litigants who believe that certain government action constitutes an “establishment” when in fact it does not.

Can we define, in a general, principled way, an "establishment" of religion?  Or, are we stuck with a litany of state actions -- e.g., composing prayers for recitation in government schools, direct funding of religious education, etc. -- that seem clearly enough to be "establishments", even if we cannot say why?

I wonder what Fr. Araujo would think if we were to embrace -- or, at least, start our inquiry with -- the discussion provided by Justice Thomas in last year's Pledge of Allegiance case, Elk Grove v. Newdow:

The traditional “establishments of religion” to which the Establishment Clause is addressed necessarily involve actual legal coercion: “The coercion that was a hallmark of historical estab­lishments of religion was coercion of religious ortho­doxy and of financial support by force of law and threat of penalty. Typically, attendance at the state church was required; only clergy of the official church could lawfully perform sacraments; and dissenters, if tolerated, faced an array of civil disabilities. L. Levy, The Establishment Clause 4 (1986). . . .  Even if “establishment” had a broader definition, one that included support for religion generally through taxation, the element of legal coercion (by the State) would still be present. . . .

It is also conceivable that a government could “estab­lish” a religion by imbuing it with governmental authority, . . . or by “delegat[ing] its civic authority to a group chosen according to a religious criterion[.]” . . .  A religious organization that carries some measure of the authority of the State begins to look like a traditional “religious establishment,” at least when that authority can be used coercively. . . .

It is difficult to see how government practices that have nothing to do with creating or maintaining the sort of coercive state establishment described above implicate the possible liberty interest of being free from coercive state establishments.

Rick