By the end of the nineteenth century the vast majority of Latin American constitutions had presidents with a relatively high degree of autonomy from congress in the operation of government, reactive legislative power, and little or no power to promote legislative change. This design has changed radically; gradually in the early decades of the twentieth century, and more rapidly after the expansion of electoral democracy in the region since the late 1970s. One salient feature of this transformation is that whereas the government powers of presidents have generally decreased, their powers in the legislative arena, in particular to promote legislative change, have increased.