Migrant-Family Separation and Higher-Order Laws’ Diverging Normative Force

A growing experimental literature suggests that international law has a larger impact on public opinion than constitutional law. Because the former US policy of separating migrant families at the border arguably runs afoul of both the Constitution and international law, it provides an unusual opportunity to simultaneously explore the normative pull of these norms experimentally. We fielded national surveys in 2018 and 2020, asking respondents how much they supported the policy. We find that telling people that the policy is unconstitutional increases support for the policy, but only when the issue is receiving heavy media coverage, and that international law has no comparable effect on public opinion. We attempt to explain these seemingly counterintuitive results in two ways. First, in studies that explore the impact of constitutional law, respondents may be unsuccessfully treated. Second, constitutional law treatments can trigger a backlash effect through defensive processing of information about constitutionality.