I still think that the United States has been presented with the best opportunity to help change a tyranical regime from within since Poland. The United States supported the Solidarity Union not just by intel, but also by sending fax machines (no internet then) and tremendous moral support, including from the American unions (mind you, this was when Lane Kirkland was running things. A lib, but still old school. Also Pope John Paul II was a major ally against the Evil Empire.). The student movement in Iran is a repeat of what happened in Poland.
East Germany, too. This sort of thing was going on right before the Wall came down.