Net migration to the US is negative for the first time in 50 years [1] so seems ...

Net migration to the US is negative for the first time in 50 years [1] so seems way more effective than whatever was done before. As for arresting citizens - federal agents arrest ~100K people per year[2], if the often cited in these threads research to be believed then most of them are citizens as illegal migrants don't do nearly as much crime. Being a citizen does not make one immune to the federal law enforcement, even the Department of Education has armed agents, which arrest citizens, even if they don't go to school [3].