Lay Authority

I share Susan's puzzlement over why restricting the governance authority of the laity is considered necessary to "preserve the distinctiveness of the ordained priesthood."  Why are attempts to strengthen the authority of lay people in the Church almost invariably seen as challenges to the distinctiveness of the priesthood?  Are challenges to the "authority" of priesthood necessarily challenges to its "distinctiveness"?  While they might often be, in practice, I don't think they necessarily always are.  Like Susan, I have trouble understanding why this election is perceived as a threat to the distinctiveness of the priesthood.

As I was thinking about this today, I just happened to come across this quote from Hans Urs von Balthasar, in a footnote to an article I'm editing right now.  Seems pertinent to this discussion:

The realized Idea of the Church comes at the beginning; everything subsequent, even ecclesiastical office with its sacred functions, is secondary, if not unimportant, in comparison.  After all, the Church exists to serve the ransom and retrieval of the sinful world.  In Mary, the Church is embodied even before being organized in Peter.  The Church is first -- and this first is permanent -- feminine before she receives a complementary male counterpart in the form of ecclesial office.

(The Marian Mold of the Church, in Mary: Church at the Source (1997), at p. 49.