A pair of federal employees who are required to work without pay during the partial government shutdown sued for wages Dec. 31.

The employees are essential Bureau of Prisons personnel who have been working since funding lapsed Dec. 21. They worked Sat., Dec. 22, the final day of a pay period for which the regular pay passed. Their paycheck included compensation for Dec. 21 and earlier days, but not for Dec. 22, they say. The bureau is part of the Justice Department, which is among the agencies that are affected by the partial shutdown.

The federal government hasn’t met its...