"Thus, despite flowery rhetoric about the State's "substantial" and "profound" interest in "potential human life," and criticism of Roe for undervaluing that interest, the joint opinion permits the State to pursue that interest only so long as it is not too successful. As Justice BLACKMUN recognizes (with evident hope), ante, at ____, the "undue burden" standard may ultimately require the invalidation of each provision upheld today if it can be shown, on a better record, that the State is too effectively "express[ing] a preference for childbirth over abortion," ante, at ____. Reason finds no refuge in this jurisprudence of confusion."