Robert Drinan, the left-wing priest turned Massachusetts congressman, died yesterday at 86. Father Drinan was pro-choice but "personally opposed" to abortion before Mario Cuomo, for impeaching Richard Nixon before it became fashionable, and a man for whom the Social Gospel was infallible. The news story I linked to calls him "a pioneering priest."
Liberals don't mind the mixing of religion and politics. They just want religion to be mixed with politics they agree with.