Compulsory and voluntary movements

Does the commitment to compulsion indicate the truth of a religious or political movement? Not likely. How much of their actual success was do to being compelled by law to join them? Think of the Crusades, the Inquisition, the well known surrender-or-die of Islam, Stalinist Marxism, Nazism, etc etc.  James Madison and the Founders instituted the separation of church and state to avoid the ceaseless wars “that soiled the soil of Europe with blood for centuries.”

Even if a religion or political philosophy had the whole and absolute truth, there are practical reasons in the modern world not to institute compulsion. Modern movements of compulsion are snuffed out before they begin, and the world gangs up on single-issue dictators and imperialists. Ordered Evolution, not revolution, is the long-term way to go. War tends to stop evolution in its tracks, often for a long time, war can even sweep all evolutionary gains off the table.

A movement needs to be voluntary, reasonable, legal. This may be the slower way but it can be deeper and last longer... But I'd like to see some studies on the actual success, sociobiologically, or lack of success, of compulsory and voluntary religious and political movements.