WASHINGTON — Loretta Lynch won Senate approval Thursday as U.S. attorney general, becoming the first black woman to occupy the post at a time when deadly altercations between white police and unarmed black men, immigration rule,s and presidential politics are emblazoned in the national debate.After a rancorous process of bringing her nomination to a final vote, the margin of approval was wider than expected: Ten Republicans including Majority Leader Mitch McConnell joined the Senate’s 44 Democrats and two independents in supporting Lynch, 55.Forty-three senators, all Republicans including Iowa’s two Republican senators, were opposed.Sen.