Historical clue formulations

• Quisling, e.g. — 2025-07-18
• Brutus, e.g. — 2020-04-04
• Judas — 2015-09-07
• 37-Across, e.g. — 2014-08-14
• Sellout — 2012-02-09
• This isn't true — 2004-12-03
• Rat — 1997-10-09
• Brutus, e.g. — 1997-07-19
• Double agent — 1995-03-26
• Judas — 1994-06-12