Alabama's controversial immigration crackdown heads to court NEW YORK (Reuters) - Two months before the Supreme Court hears arguments over Arizona's controversial new immigration law, another courtroom battle will take center stage, this time over Alabama's immigration crackdown. On Thursday, the U.S. Court of Appeals for the 11th Circuit, based in Atlanta, will hear arguments over whether a state can pass tough new measures to crack down on illegal immigrants, a power typically reserved for the federal government. The Alabama law, which took effect in September, requires police to check the immigration status of anyone they detain and suspect of being in the country illegally. Other parts of the law make it a felony for illegal immigrants to apply for or renew drivers' licenses, identification cards or license plates. The Obama administration sued in August to block the law, accusing Alabama of interfering with the federal government's exclusive authority over immigration policy. Alabama's law goes further than Arizona's, requiring public schools to obtain the birth certificates of children upon enrollment, among other provisions. In October, the 11th Circuit temporarily blocked the school reporting requirement. The court also suspended the section that requires illegal immigrants to carry immigration documents at all times. Whatever the outcome of the two cases, it is sure to add fuel to an already fiery debate over immigration in a presidential election year. Decisions are not expected in either case until summer or later. A key question in both the Alabama and Arizona cases is the extent of the federal government's power to dictate immigration policies. Under the U.S. Constitution's Supremacy Clause, federal laws and regulations trump conflicting state laws. But when Congress passed the major federal immigration laws, it did not clearly indicate whether it intended to bar state laws in the same field. The Obama administration argues that federal immigration laws are so comprehensive that they take precedence over the Alabama and Arizona laws. Lawyers with the Department of Justice point to a 1941 case in which the Supreme Court struck down a Pennsylvania law requiring aliens to register with the state, concluding Congress intended to create a uniform federal immigration system that superseded Pennsylvania's law. The Obama administration contends that the Alabama law frustrates federal immigration objectives, which prioritize deporting illegal immigrants with criminal backgrounds. The Alabama law doesn't recognize such priorities, the government says, and instead restricts basic human needs such as enrolling one's children in school. Federal immigration law is not designed to maximize enforcement and ferret out every person unlawfully present in the United States, says David Martin, a law professor at the University of Virginia specializing in immigration and international law. Instead, it seeks to balance limited resources and relations with foreign countries. "Turning loose every sheriff to enforce immigration laws could lead to mistakes and run counter to federal policy," Martin said. Alabama argues that its new law does not conflict with the federal system but rather ramps up enforcement of existing federal policies. The new state law calls for cooperation with the U.S. government, and closely tracks federal law, the state's lawyers argue. The state relies primarily on a 1976 case, De Canas v. Bica, in which the Supreme Court found that federal immigration laws did not prohibit states from enforcing the policies behind those laws. There, the court upheld a California law prohibiting the employment of illegal immigrants. How can simply informing federal authorities of the presence of an illegal alien interfere with federal policies "unless such priorities and strategies are to avoid learning of the presence of illegal aliens?" Alabama's lawyers asked in a court filing. State lawmakers in Alabama, Arizona and other states have argued that they were forced to act due to what they consider to be the Obama administration's failure to stem the flow of illegal immigrants into the country. Alabama district court judge Sharon Lovelace Blackburn agreed with the Alabama's arguments, finding no evidence that Congress intended to block state immigration laws, provided they were in line with the federal system. Even if the state informs the federal government of illegal aliens, the federal government does not have to act on that information, she noted. That is the opposite conclusion the 9th Circuit reached in the Arizona case, which the Supreme Court will hear on April 25. The Supreme Court's decision in the upcoming Arizona case looms large over the Alabama lawsuit and will likely influence the 11th Circuit ruling, says Peter Spiro, a law professor at Temple University. Before issuing an opinion on the Alabama law, the 11th Circuit will wait to see what the high court decides on Arizona, he says. One earlier Supreme Court immigration ruling out of Arizona could bode well for Alabama. In 2011's Chamber of Commerce v. Whiting, the court's majority found that federal law does not prevent Arizona from revoking the business licenses of companies that intentionally hire undocumented workers. The state could also require employers use a federal electronic system to verify workers' immigration status. The Justice Department and the Alabama Attorney General declined to comment on the litigation.