Illinois Law dean and professor Vikram David Amar discusses a challenge to the Affordable Care Act (popularly known as Obamacare) that recently succeeded in a lower federal court. That challenge, brought by the U.S. House of Representatives, raises the threshold issue whether the House can sue the president to vindicate their legislative powers. Amar explains the few notable times the Supreme Court has considered whether legislators or legislatures could sue the executive branch, and he compares and contrasts those cases with the present challenge.