In 2008, the voters of California passed a measure requiring that egg-laying chickens be given enough room to spread their wings. The state legislature followed up with a law requiring the same standard for eggs imported from other states. California is an enormous market for eggs — and 55% of them are imported. Some farmers in other states complain that California law will require them to spend more money to raise their chickens, in violation of the Constitution's "interstate commerce" clause. With big money at stake, Congress is now divided over states' rights and federal power. Ellyn Ferguson covers agriculture for CQ Roll Call.