This chapter focus on the institutional debates around a free-womb law project. The Conservative Party´s modernizing faction, led by Prime Minister, the Viscount of Rio Branco, proposed a free-womb law bill - inspired by Spanish legislation – on the House floor, in 1871. This action provoked a pro-slavery backlash. From the diffuse proslavery social groups (entire social strata had economic activities and a way of life-based on slave labor) emerged a politically organized pro-slavery reaction. This countermovement diffused proslavery rhetoric (a "circumstantial" defense of slavery), organized civil associations (Plantation Clubs), and formed a parliamentary bloc (the “hardliners”). On the other side, the first cycle of antislavery mobilization in the public space appeared, with public conferences, pamphlets, and the foundation of civil associations between 1868 and 1871. Resistance did not prevent the free-womb Law from being approved in 1871, liberating children born to slave mothers. It mitigated, however, the government’s original bill and postponed its full enforcement until the newborns had reached the age of eight, in 1879.