"The birth control campaigns created a religious divide in American's approach to reproductive issues. After the 1930s, few Protestants outside of fundamentalist circles preached against birth control, and many clerics from more progressive denominations joined campaigns to promote its use. By rejecting Catholic natural law-based arguments against birth control, Protestants made it more difficult to use those arguments against abortion. By the time that abortion policy became a matter of political controversy, most Protestant denominations had no consistent theological position on the subject. Catholics, by contrast, became more vocal in their denunciations of both birth control and abortion after the 1920s. American Catholic priests were preaching against birth control long before Casti Connubii, but the encyclical encouraged their efforts and gave renewed vigor to their campaign. Warnings against the use of contraception appeared in Catholic diocesan papers and Sunday homilies, and premarital counseling sessions for Catholic couples invariably included instruction on the subject. The discussions of birth control in the mid-twentieth century laid the natural law groundwork for later arguments against abortion. Some priests even preached directly about abortion as early as the 1930s."