Just as GOP front-runner Donald Trump continued to shore up delegates, winning several Super Tuesday states, some top Republican strategists and donors began to line up behind a new effort to halt the Trump campaign's momentum. Jeb Bush's former communications director, Tim Miller, announced Tuesday that he would be joining the Our Principles PAC, an anti-Trump effort. Miller will focus on opposition research that will go to expanding the PAC's advertising campaigns - including research targeting endorsers and surrogates like Chris Christie. Other strategists and big name donors - like technology executive Meg Whitman, billionaire Todd Ricketts, and hedge fund...