Two dynamics are fundamentally reshaping the structure and functioning of the American government. The first, which is quite well known, is Congress's decline. The second, perhaps somewhat less appreciated but no less significant, is the Supreme Court's ascent"its expansion of its power into areas previously thought to be off-limits. These dynamics share a root cause: the partisan polarization that has reshaped American politics over the past four decades. But the connection is deeper and more complex than that. Whereas polarization weakened Congress, it emboldened the Court to dismantle laws and, in the process, undermine Congress's ability to make laws at all, reinforcing Congress's sclerosis.