HOUSTON - In a shift of tactics, Republican presidential contender Rudolph Giuliani acknowledged his liberal views Friday, calling a woman's right to choose an abortion one of his "core beliefs." After a week of criticism for making contradictory comments about abortion, Giuliani also said he backs gay domestic partnerships that aren't marriage and the right of states to restrict guns. Giuliani, a New York Catholic who once considered the priesthood, chose to make his stand before a conservative, Protestant audience at Houston Baptist University in an appearance arranged just Wednesday.