Since Hamas's electoral victory, Israel and the world have been faced with new policy challenges: What should be the future of donor assistance? How should we view a Palestinian national unity government? Should Mahmoud Abbas's offer to view the PLO as Israel's interlocutor be accepted? These questions, as pressing as they are, all converge on a single challenge: ensuring that the swearing-in of the new Hamas government will be turned into a major setback for Islamic extremism. This can be done, but the window for doing so is short, requiring a coherent and determined approach. This window of opportunity has opened because the elections prematurely ejected Hamas from its comfortable position as the backseat driver of the Israeli-Palestinian political process. Hamas had the luxury of repeatedly derailing progress through terror while framing Fatah and the Palestinian Authority as a failure. At the same time, a weak and corrupt PA served as political buffer, contributing to Hamas's popularity and power. What Hamas did not plan on is sitting squarely in the driver's seat. Though polls indicate that only 15-20 percent of Palestinians endorse Hamas ideology, 44% of the electorate voted in its favor. The quirks of a regional election system further amplified Hamas's power into about 60% of the seats in the Palestinian Legislative Council (PLC). FOR NOW, security forces and key diplomatic and economic positions remain in the hands of Fatah while Abbas has veto power over any legislation. Hamas needs time to digest the PA and close the gap between its political over-representation and actual weak power. A relevant historical reference may be the Iranian Revolution of 1979, where a broad coalition ousted the Shah. Shortly thereafter, the Islamic faction turned on its former allies in a bloodbath leading to its absolute political power ever since. This may well be Hamas's plan. The key to taking advantage of Hamas's temporary weakness is keeping what New York Times columnist Thomas Friedman calls a "burning platform" under its political feet. Israel and the world can force Hamas into to a set of choices between its ideology and terror infrastructure, on the one hand, and the security and wellbeing of the Palestinian population, on the other. Either Hamas would be forced to moderate, or its power could decline due to tensions between moderates and radicals. For the "burning platform" strategy to be effective, certain conditions need to be met. First, Hamas needs to be kept in the the driver's seat, away from the comforts of backseat driving. Second, demands from the Palestinian side have to be clear, resonate with moderate Palestinians and follow internationally-accepted logic. Third, Israel needs to use its policy tools to force Hamas to make hard choices. KEEPING HAMAS in the driver's seat requires a restructuring of the political process by framing the PA - led by Hamas and Abbas - and not the PLO or the Hamas movement as the formal interlocutor and the subject of the world's demands. The PLO should no longer be viewed as the Palestinian political address, as its status as the "sole legitimate representative" has been irrevocably eroded by the existence of a democratically elected leadership that must serve as an updated "address." Assuming the leadership of the PA has not been enough of a reason for Hamas to seek to fully position itself in the Palestinian decision-making driver's seat. Recreating the comforts of backseat driving requires Abbas, Salam Fayyed and their ilk to serve as political buffer. Hamas has not been short of ideas: A government of technocrats or a national unity government are just two of them. In this context, Hamas's generous offers to Fatah to participate in the new government make perfect sense. Naturally, Hamas's weakness may serve Fatah, which is happy to continue to preserve its positions and the fa ade of authority. What, then, should Israel and the rest of the world demand of the PA? The fundamental principle is that of succession, which mandates governments to comply with commitments made by their predecessors. As Hamas explicitly rejected agreements with Israel, the world should insist on formal reaffirmation by the PLC, on behalf of the PA, of all existing agreements. In particular, the PLC should reaffirm Yasser Arafat's letter to Yitzhak Rabin of September 9th, 1993 recognizing Israel, accepting Security Council Resolution 242 and renouncing the use of violence; Oslo's Interim Agreement, including all economic and security arrangements; and the road map, which calls for consolidating all armed factions under the PA, hence dismantling the Hamas terror infrastructure. To enforce these demands, Israel should state that it will no longer be bound by agreements signed by the PLO but not reaffirmed by the PLC, the elected power behind the throne. Once the PLC has done so, the next set of demands should focus on Hamas's implementation of these commitments. In order to avoid this scenario and the direct international pressure it would bring, some Hamas officials have claimed that the PA does not need to reaffirm agreements signed by the PLO, or does not have the power to do so. Constitutionally and according to Oslo they are right: the PLO is the interlocutor. But this approach is overly formal; prospects for political progress without PLC affirmation are slim. Israel's decision to halt the transfer of customs revenue is a step in the right direction, but may fall short of imposing sufficient pressure on Hamas. Israel should consider harsher measures, such as impeding the movement of goods and labor, since the issue is as much about whether hardship is created as it is about who is framed as responsible for it. If the Hamas-led PA rejects existing agreements and the principle of governmental succession, the responsibility for the economic hardship should fall squarely on its shoulders. VICTORY IN PLC elections is just a stepping stone for Hamas. Its long-term objective is to lead the entire Palestinian national movement. Hamas is gearing up for a hostile takeover of a political shell company - the PLO - which, though politically empty, is recognized as sole legitimate representative of the entire Palestinian people, including the refugees. This objective requires staying in the backseat and gradual building of political force. Hamas's mistimed ascendance has made it more vulnerable than ever to an erosion of its power. The advent of the new Palestinian government is a historic opportunity to generate a crisis that may lead to an ideological change in Hamas, the dismantling of its terror infrastructure or at least to a deep division within its ranks. If the West works to keep the "platform burning," Hamas's great moment can be turned into a Pyrrhic victory. The writer is the president of the Re'ut Institute (www.reut-institute.org). He served on the Israeli delegation to the negotiations with the PLO from 1999 to 2001.