Lawyers say ICE can still deport serious criminals, but not under a vague standard.

During the presidential campaign, Trump highlighted the murder of 32-year-old Kathryn Steinle, who was shot by a Mexican immigrant who had unlawfully re-entered the country after being convicted of a separate crime and deported.Now, Republicans are working on legislation to impose a mandatory five-year minimum prison sentence for immigrants who have twice been charged with illegally re-entering the country or have prior aggravated felony convictions.

The Supreme Court tried to figure out Tuesday whether immigrants should get a second chance in court when bad legal advice leads to a guilty plea and certain deportation.

The mistaken citizenships were granted, the Department of Homeland Security explained in a press release, because neither its digital fingerprint repository nor the FBI’s fingerprint repository contain exhaustive records of individuals who have previously been deported.

Trump cites figures about criminal aliens as hard facts, but they are not reliable data points.