Historical clue formulations

• Silencer — 2015-01-22
• Discussion stopper — 2012-08-24
• Debate stopper — 2003-09-07
• Speech impediment? — 2002-05-02
• Ban on talking — 2001-02-05
• Debate restriction — 1996-11-16
• Debate stifler — 1994-02-21