The United States' recent request for a public clarification from National Security Adviser Uzi Arad following the IDF's killing of three wanted Al-Aksa Martyrs Brigades terrorists in Nablus is unusual and raises questions. Arad's reported need to explain to his US counterparts the defensive nature of the IDF operation several days after the Iranian-backed terror cell's murder of Rabbi Meir Chai, a father of seven, seems exceptional. This IDF operation was no different than hundreds of other actions against Palestinian terror groups that have murdered well over 1,000 Israeli civilians since the Palestinian Authority launched the Aksa war of terror in 2000. As a rule, the US has not asked Israel for public clarifications on antiterror operations. Clearly, close communications are important. There are multiple security and intelligence channels between Israel and its closest ally that have been and should be used to handle these types of security queries. The Israeli Embassy in Washington, the US Embassy in Tel Aviv, the US consulate in Jerusalem, military attaches and representatives of respective intelligence agencies are appropriate addresses. But in this extraordinary case, the US demanded a public clarification on behalf of the PA. This clearly represents heightened US sensitivity to Palestinian protests over the IDF's "unjust" incursion into Area A of Judea and Samaria/the West Bank, where the PA has overall security responsibility, to net the Fatah-associated terror cell that resulted in its elimination. THIS IS where it seems more appropriate that the US issue clarifications to Israel. At least one of the Aksa Brigades commanders - Annan Sabuh, who was found with two M16 automatic rifles and two other firearms - had been part of the amnesty program for former Fatah-affiliated terror group commanders and operatives that was predicated on turning in all weapons. The amnesty program was implemented in no small part at the behest of the United States and its security reform program, which began under Lt.-Gen. Keith Dayton in 2005. Notwithstanding IDF praise for PA public policing improvements in some West Bank cities and for PA security actions against Hamas, the American-trained and -funded Palestinian security forces under the command of PA Prime Minister Salam Fayyad have either refused or been unable to uproot the terror infrastructure of the Fatah-associated Aksa Martyrs Brigades. Similar to the three recently neutralized terrorists, thousands of additional Aksa Martyrs operatives and other Fatah militia members have gone into "retirement" via the amnesty agreement with the PA security forces and their US security coordinators, but many operatives still store weapons in their homes. US security officials may also be aware that some Fatah terror operatives have even been sheltered in PA security installations to remove them from Israel's most wanted list. Fayyad has also coopted some Aksa commanders by assigning them to senior positions in the PA security forces, such as Abu Jabbal, a senior PA security forces officer in Nablus. The increased US commitment in 2009, equaling some $130 million to upgrade the PA forces to nearly 3,500 men, has failed to address the very problem of the continued existence of Al-Aksa Martyrs Brigades and other armed Fatah factions that resulted in the recent murder of Chai. It is well known in senior Fatah security echelons that the limited capacity and political will of PA forces require the IDF to assume between 70 percent and 80% of the security operations against the extant terror infrastructure in the West Bank. ASSERTIONS BY some US officials as to the effectiveness of PA security forces must also be reassessed in view of recent Aksa Martyrs actions against the Palestinian leadership. Aksa operatives fired shots recently at Anan Atiri, deputy to the incoming governor of Nablus, after publishing leaflets labeling the governor a traitor. The group has also publicly labeled Fayyad an American agent and has published threats against him. Add this to the fact that Al-Aksa Martyrs Brigades shot at outgoing Nablus Governor Jamal Muheissin on November 26, and that in May it published a leaflet there accusing PA President Mahmoud Abbas of participating in assassinations in Palestinian refugee camps in Lebanon. In view of the Aksa Martyrs Brigades' direct challenge to the US-backed PA Security forces, it would seem appropriate for to Israel to receive clarifications from the United States as to how these robustly funded and well trained paramilitary forces plan to finally uproot the Fatah and Hamas terror infrastructures that continue to claim the lives of Israeli civilians while physically threatening the PA leadership that is supposed to be securing the foundation for independence. The United States might also clarify to the Palestinian leadership that in the aftermath of the tragic and violent Iranian-backed Hamas takeover of Gaza following Israel's 2005 withdrawal, Israelis are not inclined to assume major security risks in line with Palestinian "red line" demands for a second complete Gaza-type withdrawal, particularly in Area C of the West Bank, which houses the strategically vital Jordan Valley and its 3,000-foot protective hills overlooking Israel's major coastal cities. To be sure, Israel will become even more risk-averse if the Palestinian Authority proves incapable of completely uprooting the entire terror infrastructure in the areas under their agreed upon jurisdiction. The writer is director of the Institute for Contemporary Affairs and a senior policy analyst at the Jerusalem Center for Public Affairs.