MICHELLE NICHOLS  THE United States unilaterally blacklisted Libya's Kaniyat militia and its leader on Wednesday after Russia last week prevented a U.N. Security Council committee from imposing sanctions over human rights abuses by the group. The U.S. sanctions were imposed under the Global Magnitsky Act, which allows the U.S. government to target human rights violators worldwide by freezing assets and prohibiting Americans from doing business with them. "Mohamed al-Kani and the Kaniyat militia have tortured and killed civilians during a cruel campaign of oppression in Libya," U.S. Treasury Secretary Steven Mnuchin said in a statement. The United States and Germany…