from Mexico
https://wws.princeton.edu/system/files/research/documents/684200.pdf
It's pretty long, and in fact, I haven't even finished reading it, but the conclusion struck me as relevant as "solutions" to immigration issues are being debated:
CONCLUSION AND DISCUSSION
The principal substantive finding of our analysis is that border enforcement
was not an efficacious strategy for controlling Mexican immigration
to the United States, to say the least. Indeed, it backfired by cutting off a
long-standing tradition of migratory circulation and promoting the largescale
settlement of undocumented migrants who otherwise would have
continued moving back and forth across the border. This outcome occurred
because the strategy of border enforcement was not grounded in any realistic
appraisal of undocumented migration itself but in the social construction
of a border crisis for purposes of resource acquisition and political
mobilization. Although these arguments have been made previously, never
before have instrumental variable methods been applied to such a wide
range of border outcomes and migrant behaviors to assess the causal effect
of U.S. border enforcement.