As stated before, the PDF main role as a tool for political control of the population by intimidation, coercion and even direct aggression, instead of the legitimate role of armed forces in national defense, was proved when they showed to be largely ineffective as a combat force during Operation Just Cause, when U.S. Forces invaded Panama and overthrew Noriega in 1989, where only some individuals (including last-minute civilian volunteers who despite opposing the regime considered their duty to fight against foreign forces), small units, and in some cases even the Dignity Battalions presented more armed resistance.