The paper deals with the issue of abortion law in a comparative perspective. Despite the scientific progress, the regulation of abortion represents an insidious field, which involves extra legal issues, such as the status recognized to the unborn, the freedom of choice of the woman and the right to life of the unborn. Moreover, since it arose in the public sphere, it has polarized civil societies. The paper compares the evolution of abortion law in the USA and in Europe, arguing that the federal principle may represent an effective tool in order to address abortion regulation avoiding the polarization of the competing perspectives on the rights at stake. The paper will show this role of federalism through the lenses of the case law and of the role of the judiciary in the USA and in Europe (with particular focus on Germany, Ireland and Italy).