Justice Anthony Kennedy cast the fifth vote in 2004 to reject a gerrymandering claim from Pennsylvania, but said a state would cross the line if one party freely admitted it drew the districts to deny the other party's "right to fair and effective representation." He also warned of the "threat" posed by computer programs that make it easier for lawmakers to draw district lines to rig outcomes. If the courts don't intervene, he wrote then, "the temptation to use partisan favoritism in districting in an unconstitutional manner will grow."