Last week a fiery-eyed grocer's son stood among 2,000 cheering Moroccans in a Casablanca movie house to announce the formation of a new political party, the National Union of Popular Forces. It was the most important political development in Morocco since the North African kingdom got its independence 3½ years ago, and it made its leader, 39-year-old Mehdi ben Barka, the most important man in Morocco next to King Mohammed V and the monarchy's unquestioned challenger.
For 15 years Morocco's only major political force has been the Istiqlal (Independence) Party, a coalition of wealthy landowners, eager left-wing social reformers and skillful...