The ongoing rivalry between Hamas and Fatah culminated in Hamas’ the seizure of power in Gaza (June 2007). One bone of contention was who would control Palestinian security services. If Fatah continued to dominate the police and intelligence forces, it could curb domestic opponents and restrain unauthorized violence against Israel. These goals were anathema to Hamas, especially after the party won legislative elections (January 2006). Hamas formed its own Executive Force, which orchestrated the seizure of power in Gaza. This paper addresses two questions. First, how can security sector reform be advanced in Palestine, so that police and other personnel are dedicated to advancing the human security of citizens instead of settling scores between rival elites? Second, how can the United States and other members of the international community advance a human security agenda? The Bush Administration sponsored the training of Palestinian police with a counterinsurgency mission targeted against Hamas and a political objective of strengthening Fatah. What vision should guide the Obama Administration in promoting diplomacy and Palestinian security? For the United States, Israel’s security requirements have traditionally taken precedence over those of the Palestinians, as apparent in the Oslo Accords and subsequent diplomatic initiatives. American and Israeli insistence that the police target those launching operations against Israel undermined public confidence public in the legitimacy of Palestinian security forces. In the future, a broader framework of governance will be needed so that followers of competing political factions can gain confidence in the accountability of security personnel to the rule of law. Egyptian and other regional intermediaries have sought to promote national unity governments and ceasefire arrangements to calm repeated cycles of Israeli-Palestinian violence. But the US and other international actors can stimulate diplomatic momentum and design transitional security mechanisms to safeguard border crossings and facilitate Israeli territorial withdrawals. This paper draws upon the author’s ongoing research for a book on Palestinian security. Close scrutiny of Palestinian, American and Israeli scholarly, policy-oriented, and media sources is supplemented by interviews with several dozen academic and diplomatic personalities. The analytical framework is enriched by lessons learned from American experiences in training Iraqi and Afghan armies and police in recent years. The inadequacy of American planning for comprehensive security sector reform in Iraq and Afghanistan has generated a considerable literature, yielding cautionary guidelines that may improve the chances for fledgling Palestinian security forces to promote human security for their citizens.