Washington (CNN) Justice Sonia Sotomayor was so eager to jump into a case Wednesday concerning the tension between the federal government and states when it comes to immigration enforcement that she broke the Supreme Court's new rule that allows a lawyer to begin arguments for two minutes without interruption.

Chief Justice John Roberts stepped in and said the lawyer could address Sotomayor's question later on.

Wednesday's case concerns whether immigrants who stole Social Security numbers in an attempt to gain employment could be prosecuted under state identity theft law.

In general, when it comes to immigration, federal law regulating a certain area preempts or supersedes state law in order to avoid a patchwork of different regulations across the country. Wednesday's arguments raised the question of how far a state can go when applying its law without interfering with federal law.

At oral arguments, some of the justices questioned whether Kansas, in prosecuting immigrants under state fraud law, encroached on an area reserved for the federal government.

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