The already bloated doctrine of federal preemption must not be further engorged. On July 6, 2010, the Holder Justice Department, allegedly without consultation with President Obama, filed suit in federal district court in Arizona to block the new Arizona law intended to enforce existing federal laws against unlawful immigration, something the federal government itself has patently failed to do. The suit asks the court for, among other things, an order restraining Arizona from implementing the new statute later this month as scheduled, pending the outcome of the litigation. It is evident that this was done for partisan political purposes, although...