In a historic move, imprisoned Kurdish separatist leader Abdullah Ocalan urged members of the banned Kurdistan Workers' Party (PKK) on Thursday to lay down their weapons in order to end a decades-long conflict with the Turkish government. While Turkey, the United States, and other countries classify Mr. Ocalan as a terrorist and the P.K.K. as a terrorist organization, many Kurds view Mr. Ocalan as a powerful symbol of the struggle for Kurdish rights.

If the PKK acts on Ocalan's call for disarmament, it could have far-reaching implications for the entire Middle East, particularly for the millions...