Politico.com reports: In a brief filed Tuesday, the Justice Department asked the Supreme Court to find unconstitutional Arizona's law aimed at cracking down on illegal immigrants. "Petitioners assert that Arizona’s status as a border State that is particularly affected by illegal immigrationjustifies its adoption of its own policy directed to foreign nationals. But the framers recognized that the 'bordering States…will be those who, under the impulse of sudden irritation, and a quick sense of apparent interest or injury,' might take action that undermines relations with other nations, and regarded that possibility as a further reason to vest authority over foreign affairs in the National government," says the brief filed by Solicitor General Donald Verrilli.
The Framers' quote is from Federalist No. 3, written by John Jay. One interesting note about the U.S. Government brief: it was signed by State Department Legal Adviser (and former Yale Law School dean) Harold Koh, underscoring the foreign policy-related argument against the Arizona statute.
Arizona's opening brief is posted here. The case is set to be argued before the high court on April 25.