Philippine Vote on Muslim Self-Rule Puts Christians on Edge

COTABATO, Philippines—Voters in a Muslim-majority region in the Philippines will decide on a proposal for greater self determination, a pivotal attempt at peace that tests the fragile relationship between Muslims and a Roman Catholic minority concerned about creeping Islamic authority.

To most of the four million people on the southern island of Mindanao, the vote offers a hopeful end to decades of conflict between armed groups and the government in this overwhelmingly Catholic country of 100 million people. The fighting claimed...