What law of June 1794 eliminated defense witnesses in revolutionary trials?

The Law of 22 Prairial eliminated the use of defense witnesses in revolutionary trials. Enacted on 10 June 1794—22 Prairial, Year II, in the French Republican calendar—it radically shortened proceedings before the Revolutionary Tribunal.

Proposed by Georges Couthon with support from Maximilien Robespierre, the law was introduced during the Great Terror. It broadened the definition of “enemies of the people,” allowed judges and jurors to rely on broadly defined moral or material evidence, and restricted the accused’s ability to challenge the case. Defense counsel was also generally denied to those labeled conspirators.

The law reduced the Tribunal’s possible verdicts to acquittal or death. Although its text allowed witnesses in limited circumstances when the Tribunal considered them necessary, its practical effect was to remove ordinary defense testimony and accelerate convictions. This is why it is commonly identified as the measure that eliminated defense witnesses in revolutionary trials.

A common mix-up is with the Law of Suspects, passed in September 1793, which expanded who could be arrested. The Law of 22 Prairial instead focused on judicial procedure and helped intensify the Terror.