The spectacle was sickeningly familiar. Thousands of refugees, most of them Rwandan Hutu, clogged the rutted roads of central Africa last week. Thousands of men, women and children were on the move in Burundi, fleeing camps where they had sought asylum last year from the civil war in their homeland next door. Now, spurred by the dread of more ethnic killing, they trudged east toward Tanzania. As they passed other Hutu camps, more thousands gathered up their meager belongings to join the trek. About 40,000 refugees were stalled Saturday just outside Tanzania after the country closed its borders.
For months, sporadic...