WASHINGTON (AP) — The Senate’s deal to avert a showdown over its internal rules and confirm several long-stalled Obama administration nominees could upend a major case at the Supreme Court, one that would test the president’s power to use recess appointments to fill high-level posts.

The case is shaping up as a major clash between President Barack Obama and congressional Republicans over the power granted the president in the Constitution to make temporary appointments to fill positions that otherwise require confirmation by the Senate, but only when the Senate is in recess.