Between January 2021 and January 2024, CBP had more than six million 
encounters with unauthorized migrants on the Mexico-US border. Another 
two million migrants were detected entering the US but were not 
apprehended.
Many of the foreigners who entered the US illegally sought out 
Customs and Border Protection officers and applied for asylum. There is a
 backlog of three million immigration cases, including a million asylum 
cases, and space to detain fewer than 50,000 foreigners who are awaiting
 hearings before immigration judges. As a result, solo adult migrants 
who pass a credible fear test, meaning they have a 10 percent 
probability of being persecuted at home, are typically released into the
 US along with families with children and unaccompanied minors under 18.
 Immigration judges reject most asylum claims, but the backlog ensures 
that migrants can work in the US for several years while their children 
attend K-12 schools.