The Arizona legislature challenged in federal court the authority of the Independent Redistricting Commission to draw congressional boundaries. The lawsuit alleges that only the legislature may create new districts for Arizona’s congressional delegation. The suit came shortly after a vote giving House and Senate leaders permission to sue.

Joseph Kanefield, a commission attorney, said a federal case settled the issue nearly a century ago. The U.S. Supreme Court in 1916 concluded that a state’s legislative authority rests not only in its legislature but also in the people, who can decide issues by referendum. Arizona voters created the commission in a referendum vote that amended the state constitution and gave the commission the power to draw legislative and congressional boundaries.

“The people were perfectly within their rights to empower themselves and create this independent commission,” said Mr. Kanefield, a litigation partner in Ballard Spahr’s Phoenix office.