segment, including a requirement that cops check people's immigration status if officers have already stopped them for some other reason and suspect, for some reason, that they are in the country illegally. arizona is appealing the ruling. today, both sides made their cases before the ninth circuit of appeals in california. claudia cowan live at the courthouse in san francisco. what was the main argument today, claudia. >> shepard, the key issue here is how far local authorities can go to regulate immigration, an area of the constitution largely leaves to the federal government. arguing before a three-judge panel here today, the government's lawyers said that arizona strictly cannot be allowed to enforce immigration rules on its own. >> if every state did this, we would have a patchwork of laws as the third circuit's decision in lozono which struck down a similar law concluded. >> all we're asking is for the federal government to their doo their job. we cannot sustain the illegal immigration. >> the day before the election, arizona governor jan brewer sat