Historical clue formulations

• One involved in a dispute — 2021-04-23
• Mosquito from the state nicknamed Land of Opportunity? — 2019-02-12
• One who settles arguments — 2017-09-07
• Ruling party? — 2015-08-27
• Judge — 2011-08-12
• Judge — 2006-07-06
• Decisive one — 2000-04-16
• Judge — 1999-12-06
• One who makes calls — 1999-01-30
• Umpire — 1997-10-05