Potential Republican candidates tread carefully on Islamic State

By Steve Holland and Alistair Bell WASHINGTON (Reuters) - Republicans exploring a 2016 White House run are pounding away at President Barack Obama's strategy for stopping Islamic State militants but, wary of Americans' war fatigue, are so far providing few specifics on what they would do differently. The renewed threat posed by Islamic militants is emerging as the top foreign policy issue for the 2016 race, and Obama's submission to Congress on Wednesday of a draft authorization o