Brett Kavanaugh walloped by John Roberts in ruling on Trump immigration policy

Chief Justice John Roberts took a swipe at the Supreme Court's newest justice, Brett Kavanaugh, in the ruling that blocks the Trump administration from ending protections under Deferred Action for Childhood Arrivals policy.

The administration has tried for years to "wind down" the Obama-era program, but Roberts and the court's four liberal justices found the administration did not follow procedures required by law -- and the chief justice called out Kavanaugh's dissent by name.

"Justice Kavanaugh asserts that this 'foundational principle of administrative law' ... actually limits only what lawyers may argue, not what agencies may do," Roberts wrote in his decision. "While it is true that the Court has often rejected justifications belatedly advanced by advocates, we refer to this as a prohibition on post hoc rationalizations, not advocate rationalizations, because the problem is the timing, not the speaker."

"The functional reasons for requiring contemporaneous explanations apply with equal force regardless whether post hoc justifications are raised in court by those appearing on behalf of the agency or by agency officials themselves," he added.

Roberts continued his upbraiding into a footnote.

"Justice Kavanaugh further argues that the contemporaneous explanation requirement applies only to agency adjudications, not rulemakings," Roberts wrote. "But he cites no authority limiting this basic principle -- which the Court regularly articulates in the context of rulemakings — to adjudications. The Government does not even raise this unheralded argument."