BAGHDAD, Iraq - Their rhetoric is still stridently anti-American, but Mahdi Army militiamen are tucking away their weapons and blending into civilian life. Their leaders are keeping out of sight. In the streets of Sadr City, the strategy of Muqtada al-Sadr, the Shiite militia leader, is clear: Lie low, avoid a showdown and hope to emerge even stronger after the Americans leave. Gathered for prayers this week, at least 10,000 al-Sadr supporters raised clenched fists and chanted "No, No to America." Later, a black-turbaned cleric addressed them, dressed in a white shroud to signal readiness for martyrdom. "They claim that...