This has historically been a major problem in the U.S. I would say the current problems are somewhat similar, but in many cases they also relate to a range of individual arbitrariness because of a lack of administrative oversight and a lack of a real rule of law regime in the U.S.
I completely agree with your description of the history. I would say the analogous situation now is that of the Colombians. Colombians are the largest group of refugees in this hemisphere, and they are effectively being either denied access to asylum—which does not happen in Canada—or denied protection in ways that are clearly in contravention of the refugee convention and clearly inconsistent with what's happening in Canada. Colombians are the new Chileans, the new Guatemalans, and the new Salvadorans. Colombians are not able to apply for protection in Canada under the safe third country agreement.