Donald Trump’s order restricting birthright citizenship appeared on Friday to be headed toward being declared unconstitutional by a second federal appeals court, as judges expressed deep skepticism about a key piece of the US president’s hardline immigration agenda.

A three-judge panel of the Boston-based first US circuit court of appeals sharply questioned a lawyer with the federal justice department as to why they should overturn two lower-court judges who blocked the order from taking effect.

Those lower-court judges include one in Boston who last week reaffirmed his prior decision to block the order’s enforcement nationally, even after the US supreme court in June curbed the power of judges to broadly enjoin