The impassioned debate over the nation's immigration policy takes center stage at the Supreme Court Wednesday in a dispute over an Arizona law that punishes employers who knowingly hire workers illegally in the U.S. The outcome in this case also could signal how the court would handle the controversial and more expansive Arizona immigration enforcement law, known as SB1070. "It could take this less visible case and do something that impacts substantially on the SB1070 litigation by making some broader observations," said Peter Spiro, a professor at Temple's Beasley School of Law.