First lady Hillary Rodham Clinton yesterday launched a vigorous counterattack on behalf of her husband's beleaguered presidency, declaring that the president is the victim of a "politically motivated" prosecutor allied with a "vast right-wing conspiracy." Using a nationally televised interview as her forum, she assumed a familiar and crucial role as Bill Clinton's first defender. She said she knew him better than anyone in the world, still loved him, and fully believed his denial of allegations that he had entered into a sexual relationship with a White House intern and had urged the young woman to lie about it. The...