Federalism is supposed to allow policy to vary with local opinion and circumstances. But American politics has nationalized, with many seeing states as arenas for national political debates among partisan networks rather than opportunities for state-specific solutions. And states are even fighting about the basic ground rules of democracy. Jacob Grumbach finds that nationalization made state policy respond more to party control, with legislators responding to activist donors over public opinion, states copying electorally successful policies only from states controlled by the same party, & Republican states causing democratic backsliding.