According to the Washington Examiner, Virginia attorney general Ken Cuccinelli has issued a formal opinion recognizing that state and local law enforcement officers have authority to "inquire into the immigration status of persons stopped or arrested." The opinion, issued in response to a question from a Virginia legislator, is available here.
As Cuccinelli explains, this authority arises not (as is the case with the Arizona law) from a specific state statute directing officers to investigate immigration status, but instead from the officers' general authority to enforce state and federal law:
Indeed, it would be most surprising if state and local officers lacked the authority, where appropriate, to arrest individuals suspected of committing federal crimes such as bank robbery, kidnapping, or terrorism. State and local officers are not required to stand idly by and allow such criminals to proceed with impunity. The same holds true with criminal violations of the immigration laws.
Cuccinelli's answer shines a spotlight on the incoherence of Judge Bolton's recent decision regarding the Arizona law, which prevents enforcement of the Arizona statute. Even Judge Bolton does not deny that state and local law enforcement may check the immigration status of lawfully detained suspects. At footnote 12 of her opinion, Judge Bolton notes that "[m]any law enforcement officials already have the discretion to verify immigration status if they have reasonable suspicion, in the absence of S.B. 1070." Indeed, she cites the federal government's own brief, which stresses that the Obama administration does not deny that states have authority "to verify immigration status in a manner that is consistent with federal priorities and that will not unduly burden either federal resources or the interests of lawfully present aliens." The Obama administration's criticism, and in turn Judge Bolton's, is that a state law requiring state law enforcement to check immigration status under certain circumstances would threaten to overwhelm federal resources.
If the Obama administration ultimately succeeds in nullifying Arizona's law, then the future may well lie in Virginia: State and local law enforcement officials will be left to exercise the state's unquestioned discretionary authority on a purely case-by-case basis. The lack of a formal state statute or regulation expressly codifying the policy will make lawsuits all the more difficult, as plaintiffs will not be able to press a facial challenge against the statute/regulation prior to enforcement of the policy.