Before it goes into effect on July 29th, the Department of Justice has filed a lawsuit against Arizona's new immigration law, which makes it a state crime to be in the country illegally, and requires anyone whom police reasonably suspect to be an illegal alien (i.e. Mexicans) to produce documents of proof that they are citizens or legal residents. They say the federal government has "preeminent authority" over immigration, and that the law is "invalid." The suit claims, "The United States Constitution forbids Arizona from supplanting the federal government's immigration regime with its own state-specific immigration policy. A policy that, in purpose and effect, interferes with the numerous interests the federal government must balance."

Attorney General Eric Holder told the Wall Street Journal that "setting immigration policy and enforcing immigration laws is a national responsibility. Seeking to address the issue through a patchwork of state laws will only create more problems than it solves." But supporters of the law say the Justice Department and the Obama administration are being too soft on immigration laws. Twenty Republican congressmen protested the lawsuit, writing to Holder, "Not only does this lawsuit reveal the Obama administration's contempt for immigration laws and the people of Arizona, it reveals contempt for the majority of the American people who support Arizona's efforts to reduce human smuggling, drug trafficking and illegal immigration."

Arizona Governor and defendant Jan Brewer called the lawsuit a "disappointment," but assured supporters, "We'll meet them in court ... and we will win." Critics, including President Barack Obama, say the law could lead to racial profiling. Obama said in a speech on immigration last week, "These laws also have the potential of violating the rights of innocent American citizens and legal residents, making them subject to possible stops or questioning because of what they look like or how they sound." He has yet to issue a statement about the lawsuit.

Many New Yorkers have had their issues with the law as well, holding protests and demanding the MLB All Star game in Phoenix be moved unless the law is repealed. Mayor Bloomberg directed his anger at both Arizona and the federal government, and said, "We have to get real about the 12 million undocumented here. We're not going to deport them. Give them permanent status. Don't make them citizens unless they can qualify, but give them permanent status and let's get on with this."