"In this Aug. 13, 2014, photo, former Secretary of State Hillary Rodham Clinton holds her memoir ""Hard Choices"" at Bunch of Grapes Bookstore, in Vineyard Haven, Mass., on the island of Martha's Vineyard, during a book signing event for her memoir ""Hard Choices.""  Clinton's split with President Barack Obama over a foreign policy ""organizing principle"" isn't likely to be the last time differences emerge between the two. How she handles those breaks could be among her biggest challenges to a successful run for president in 2016. (AP Photo/Steven Senne)"
{}