"Lefty secular" and "just"

In response to Michael's post:  Rob cited, as examples of "a strangely perfect convergence between Christianity and lefty secular social policy," the positions of the Episcopal Diocese of New York on abortion ("The Diocese supports freedom of choice in abortion") and school vouchers ("none but public schools should be supported with public monies").  Then, after noting that some conservative Republicans support a right to same-sex marriage, and also that there are strong theological arguments in favor of legal recognition of same-sex marriages, Michael suggested what Rob refers to as a "a strangely perfect convergence between Christianity and lefty secular social policy" is "better described as a strangely perfect convergence between Christianity and just social policy.  Put that way," Michael continued, "the convergence is not 'strange' after all.  It's just what we should expect, later if not sooner."

Two quick points:  I am confident that Michael agrees me that the positions of the Episcopal Diocese of New York, cited by Rob as evidence of a convenient "convergence" between Christianity and "lefty secular"  social policy are, in fact, quite unjust.

Next, and more seriously:  Is it really that case that we should -- this side of heaven -- "expect" perfect convergence between Christianity and just social policy?  What would be the content of such expectations in a secular, democratic society?