Even as Israelis and Palestinians plunged deeper into conflict, US President-elect Barack Obama remained silent, refusing to budge from his one-president-at-a-time mantra. Obama takes office on Jan. 20 but has not commented on the Middle East crisis since Israel launched attacks on Gaza nine days ago. His advisers insist that only President George W. Bush can speak for America until then. The Palestinian death toll in nine days of Israeli attacks has risen to more than 500. Hamas, which ended a six-month ceasefire, has fired rockets deeper into Israel than ever before, hitting major cities and killing four Israelis. While most prominent US politicians have backed Israel, critics have noted that Obama joined Bush in condemning the killing of civilians in attacks in November in Mumbai, India. They would have liked him to say something about the fate of Palestinian civilians caught in the fighting. The president-elect also has commented on the global economic crisis and his plans to try to pull the US economy out of recession. Asked about the apparent contradiction, an Obama transition aide who asked not to be named said on Sunday: “President Bush is our nation's president until Jan. 20, and he is responsible for our nation's diplomacy with the world. “During this transition period, we are not engaging in any action that could send confusing signals to the world about who speaks on behalf of the United States.” Politics, diplomacy Domestic politics and international diplomacy could be factors in Obama's silence. He may hope the crisis will reach a turning point where a new president, untarnished by previous comments, can make a difference with a fresh start. He also knows any statement is fraught with traps. “If I were Obama, I wouldn't want to talk about it either. Frankly, it's a lot more comfortable to let this one hang on the president,” said Edward Walker Jr., who served as US ambassador to Israel from 1997 to 1999. “I don't think he wants to be tagged at this point with either advocating the Israeli response or condemning it because our (US) interests are sort of torn on this one,” added Walker, an analyst with the Middle East Institute think tank. Pro-Israeli comments by Obama risk upsetting the Arab world even before he takes office. Comments that seem critical of Israel would anger its American supporters. Morton Klein, president of the pro-Israel Zionist Organization of America, noted that Obama spoke out on Mumbai. “And he's acting almost as if he's president when it comes to the economy, right? He's not screaming ‘there's only one president' when he's talking about the economic stimulus package,” Klein said. Flexibility James Carafano, a defense expert at the Heritage Foundation think tank, said Obama may not want to comment on foreign policy issues like Gaza because “you're going to be held accountable for anything that you say. “The Mumbai attacks, that's a one-time attack, the thing's over, you say some platitudes – you're not making any policy,” Carafano said. “If Obama weighed in now on Hamas and Israel, people would take that as policy. But there's two weeks between now and his inauguration. Events on the ground could change significantly. So in a sense you would walk into office with no flexibility.” There's nothing in Obama's campaign statements or those of Hillary Clinton, his choice for secretary of state, to suggest they would steer a different course from Bush. “In terms of negotiations with Hamas, it is very hard to negotiate with a group that is not representative of a nation-state, does not recognize your right to exist, has consistently used terror as a weapon, and is deeply influenced by other countries,” Obama said in July. In a CBS interview a week ago, Obama's aide David Axelrod recalled that when then-candidate Obama visited the southern Israeli town of Sderot in July, he voiced understanding for Israel's urge to end Hamas rocket attacks on Sderot from Gaza. On the broader issue of Middle East peace, Obama promised to engage in Israeli-Palestinian peacemaking from the start but has yet to propose a policy shift that might rescue a two-state solution from oblivion. Unlike other major governments, the Bush administration has not called for an immediate ceasefire between Israel and Hamas, insisting that any ceasefire be “durable and sustainable” and that Israel avoid killing civilians.