Key points are not available for this paper at this time.
R. Michael Alvarez, John Brehm, American Ambivalence Towards Abortion Policy: Development of a Heteroskedastic Probit Model of Competing Values, American Journal of Political Science, Vol. 39, No. 4 (Nov., 1995), pp. 1055-1082
Alvarez et al. (Wed,) studied this question.