“In 1963, the Supreme Court handed down Gideon v. Wainwright, which held that the government had to provide a lawyer to any poor defendant facing prison time. While often trumpeted as one of the Court’s greatest modern decisions, it has also been embroiled in controversy from the beginning. Like all Supreme Court opinions that impose new obligations on state governments, Gideon was an unfunded mandate — and, given the political unpopularity of criminal defendants, the states have aggressively gone out of their way to make sure that this constitutional obligation stays unfunded.”