Editor’s Note: The United States rightly regards the Muslim Brotherhood-affiliated Palestinian organization Hamas as a terrorist group, but Hamas is also the de facto government of the Gaza Strip. There it juggles the responsibilities of governing Gaza and the associated need to mollify Israel with its self-image as an Islamic “resistance” movement. Making this difficult act even harder, Hamas faces a terrorism problem of its own. Gaza is home to a range of groups that see Hamas as too accommodating toward Israel and too lenient when it comes to imposing Islamic law at home. Beverley Milton-Edwards, a professor at Queen’s University Belfast and renowned expert on Hamas, assesses these Islamist rivals and the risks for Hamas of being too confrontational or too passive in dealing with them.