Justice Department VS Arizona illegal-immigration law. Top Justice Department officials have drafted a legal challenge that could be filed in federal court in Arizona asserting that the state's new immigration law is unconstitutional because it impinges on the federal government's inherent authority to police the nation's southwest border with Mexico, sources said Wednesday.

A dozen or more states are considering legislation mirroring the Arizona law, which goes into effect in July. That groundswell of support is part of what is pushing Holder and the White House to consider swift action against the Arizona law.

Under the Arizona law, police are required to ask people who are stopped because of a "reasonable suspicion" that they are in the country illegally for documents. The offense would be similar to criminal trespassing, and violators would then be turned over to federal authorities for deportation.