Arizona immigration law: Supreme Court again examines federal power The Supreme Court will conclude one of its most significant and controversial terms in decades by taking on one more issue that has divided the nation: Arizona's crackdown on illegal immigrants. The court's final oral argument on Wednesday - Arizona v. United States - provides yet another chance for the justices to confront fundamental questions about the power of the federal government. And the rulings the court will issue between now and the end of June could dramatically alter the nation's election-year landscape. (JOSHUA LOTT/REUTERS) - Presumptive Republican presidential candidate Mitt Romney speaks at a rally in Arizona in front of their state flag on April 20. Romney's tough stance against illegal immigration has angered some interest groups and is said to have cost him among increasingly influential Latino voters. The incumbent senator survives a tea party challenge but will have to run in a June 26 primary. The court has considered President Obama's health-care law, has taken its first look at the political redistricting battles being fought across the nation and will decide whether federal regulators still hold the authority to police the nation's airwaves. The Obama administration has moved aggressively against Arizona's SB 1070, which directs law enforcement to play a much more active role in identifying illegal immigrants and makes it a crime for them to seek work. The administration has persuaded courts to put aside key parts of the law. And, as with last month's hearings on the health-care law, in the Arizona case the government is asking the court to recognize that the Constitution gives the federal government vast powers to confront national problems, such as illegal immigration. "As the framers understood, it is the national government that has the ultimate responsibility to regulate the treatment of aliens while on American soil, because it is the nation as a whole - not any single state - that must respond to the international consequences of such treatment," Solicitor General Donald B. Verrilli Jr. told the court in the government's brief. Immigration is one of the nation's thorniest political issues. Obama and his administration have been accused of not properly securing the nation's borders and criticized for not delivering comprehensive immigration reform. Presumptive Republican presidential nominee Mitt Romney's tough stance against illegal immigration has angered some interest groups and is said to have cost him among increasingly influential Latino voters. And even as the pace of illegal immigration has slowed, it has left a changed picture of undocumented immigrants in the United States. According to the liberal Center for American Progress, 63 percent of illegal immigrants have been in the country for more than 10 years and more than 16.6 million people in the United States have at least one undocumented family member. Tom Saenz, president and general counsel of the Mexican American Legal Defense and Education Fund, said that while the legal issues in Arizona v. United States "relate to the structure of government, it is still very much a civil rights case." Beyond Arizona The decision will have implications well beyond Arizona. Several states have copied - and toughened - Arizona's law, and more are considering such steps. "This debate is not just about SB 1070," Arizona Gov. Jan Brewer (R) said in a statement when the state filed its brief in the case. Rather, it is for the constitutional principle that every state has a duty and obligation to protect its people, especially when the federal government has failed in upholding its core responsibilities.