There has been quite a buzz regarding the failure of the Obama administration to challenge a 2008 Rhode Island Executive Order which accomplished much of what Arizona seeks to accomplish through S.B. 1070.
The signing statement of the Governor, as well as the Order itself, set forth the grounds for the immigration procedures imposed, including the failure of the federal government to act. This is precisely the reason used to justify the Arizona immigration law.
The Department of Justice is challenging the Arizona law in court, but has been quiet about the Rhode Island Executive Order.
While an Executive Order could not criminalize conduct, unlike legislation, the Executive Order was sweeping in requiring verification of immigration status in numerous aspects of life controlled by the Executive Branch:
Rhode Island Illegal Immigration Control Order 2008-01 http://d1.scribdassets.com/ScribdViewer.swf
Hey, Rhode Island Already Checks Immigration Status At Traffic Stops
Saturday Night Card Game (The Arizona Immigration Bill Is Not Racist)
Leadership by the Wilfully Ignorant