The Supreme Court on Wednesday upheld Arizona state legislative districts drawn by an independent commission, rejecting claims by Republican voters that slight variations in population favoring Democrats violated the Constitution.

The Constitution “does not demand mathematical perfection” when states equalize population among legislative districts, Justice Stephen Breyer wrote for a unanimous court.

“This provides the commission the flexibility it needs to draw these legislative districts and comply with the Voting Rights Act and constitutional criteria,” said Joe Kanefield, a Phoenix attorney who represents the Arizona redistricting agency. “To the extent the allegations are that the commission was motivated by a desire to favor Democrats, it certainly didn’t achieve that result,” he added, noting that Republicans have maintained control of Arizona’s statehouse.