The main players in disputes over Arizona's immigration enforcement law:
FORMER ARIZONA LAWMAKER RUSSELL PEARCE
Role: Led the effort at the Arizona Legislature to get the state's immigration law passed.
Background: While serving in the Legislature, Pearce tapped into voter frustration over the state's role as the busiest hub for illegal entries into the United States. Pearce was the driving force behind most of the state's immigration laws. After passage of the 2010 law, he became president of the state Senate but was ousted from public office in a recall election last year. He is running for another legislative seat.
GOV. JAN BREWER:
Role: Signed the state's immigration law; her administration has defended it in court.
Background: Brewer, a Republican, served previously as Arizona's secretary of state and became governor in January 2009 after then-Democratic Gov. Janet Napolitano resigned to head the Homeland Security Department. Brewer's approval of the 2010 law and complaints about inadequate immigration enforcement by the federal government catapulted her into the national political spotlight.
U.S.DISTRICT JUDGE SUSAN BOLTON
Role: Blocked police from enforcing the law's most controversial parts but let other sections take effect.
Background: Bolton presided over all challenges to the 2010 law. In the July 2010 ruling that blocked the law's most contentious sections, Bolton said she believed the Obama administration would likely succeed on some of its claims that federal law trumped state law. Bolton is a former state court judge appointed to the federal bench in 2000 by President Bill Clinton.
Role: Challenged the law in court.
Background: The core of the administration's case is that federal immigration law trumps state law -- an issue known as "pre-emption" in legal circles. The Supreme Court isn't considering the possibility of racial profiling arising from the law because the Obama administration didn't challenge it on those grounds.
IMMIGRANT RIGHTS GROUPS:
Role: Filed lawsuits contesting the law and held protests to voice complaints that the law would disproportionately affect Latinos.
Background: While having little effect in trying to block immigration proposals at the Arizona Legislature, immigrant rights supporters have taken to the streets in recent years and complained that immigrants in Arizona are being scapegoated for the country's porous borders and outdated immigration system.
MARICOPA COUNTY SHERIFF JOE ARPAIO:
Role: Staunch supporter of local law enforcement's right to fight illegal immigration with hardline tactics.
Background: Though Arpaio had no direct role in getting the 2010 law passed, the law would provide backup for the longtime sheriff of metropolitan Phoenix. Using other state and federal laws, Arpaio's office has arrested immigrant smugglers, raided businesses suspected of hiring illegal immigrants and conducted special traffic patrols that focus on illegal immigration. The U.S. Justice Department has accused Arpaio's office of racially profiling Latinos, a charge the sheriff vehemently denies.
ATTORNEY KRIS KOBACH:
Role: Helped draft Arizona's 2010 immigration enforcement law.
Background: Kobach is known nationally for advising state officials about cracking down on illegal immigration, and he helped draft tough laws in Alabama. Previously, he worked nearly two years in the U.S. Justice Department under Attorney General John Ashcroft before running unsuccessfully for Congress in 2004. He now serves as secretary of state of Kansas.