A federal judge ordered the Justice Department to send its lawyers back to remedial ethics classes Thursday after finding that the administration repeatedly misled the court in the high-profile challenge to President Obama’s deportation amnesty. In a scathing 28-page ruling, Judge Andrew S. Hanen said the lawyers knew the administration was approving amnesty applications but actively hid that information from the court and from the 26 states that had sued to stop the amnesty. Judge Hanen thought about tossing all of the government’s arguments out, but said since the merits of the case are now pending before the Supreme Court,...