American asylum policy has developed gradually over many decades, which can be divided into five distinct eras. The relationships between the categories of refugee, asylum seeker, and undocumented immigrant have shifted frequently, and answers about which asylum seekers qualify for refugee status in the United States have been both politically constructed over time and contingent on the politics of the moment. Asylum seekers, therefore, have sometimes been assumed to be refugees, and at other times have been automatically lumped together with undocumented economic migrants. Asylum policy development has also been driven by a much larger conflict in American politics: the rise of legal institutions representing a commitment to international human rights, and the conservative backlash to that emergence. All of these forces have contributed to the current era, which is characterized by deterrence policies and litigation challenging their enforcement.