Biden seeks to reassure AIPAC of U.S. commitment to Israel As Obama has done in previous appearances before the group, Biden said the administration prefers a diplomatic solution to control Iran's uranium-enrichment program, which the Islamic Republican claims is being developed for peaceful means despite mounting evidence to the contrary. But in stating Obama's pledge to Israel, Biden said, "Let me make clear what that commitment is: It is to prevent Iran from acquiring a nuclear weapon. Period. End of discussion. Prevent - not contain - prevent. "Big nations can't bluff," Biden continued. And presidents of the United States cannot and do not bluff. And President Barack Obama is not bluffing. In the heat of the U.S. presidential election, when his commitment to Israel emerged as an issue, Obama stated the same position to AIPAC last year. But Obama also warned, as international sanctions targeting Iran's financial system took hold, that, "For the sake of Israel's security, America's security, and the peace and security of the world, now is not the time for bluster." On Monday, Biden again cautioned against a rush to war, especially as a series of popular uprisings known collectively as the Arab Spring continue to remake the Middle East. He acknowledged, as Obama has, that the "window is closing" for diplomacy to work. But, he added, "We believe there is still time and space to achieve the outcome." "We are in constant dialogue, sharing information with the Israeli military, the Israeli intelligence service, the Israeli political establishment at every level, and we're taking all the steps required to get there," Biden said. Obama is scheduled to visit Israel and the Palestinian territories for his first time as president later this month, although there is an outside chance the trip could be postponed if a new Israeli government is not yet in place following January elections. Prime Minister Benjamin Netanyahu is trying to assemble his governing coalition now. Obama and Netanyahu have had an uneasy relationship over the last four years, but mainly over the Palestinian issue. At the same time, Obama has increased U.S. military aid to and collaboration on anti-missile systems with Israel. The two leaders also generally agree on the approach to Iran, although they have differed publicly at times over a possible timeline for military action against its nuclear sites. Their relationship took shape amid tensions over Obama's early approach to reviving Middle East peace talks soon after he took office. While pursuing a diplomatic effort to repair U.S. relations with the Muslim world, Obama pressured Netanyahu to cease Israeli settlement construction in the territories occupied by Israel in the 1967 war - land Palestinians view as their future state. Netanyahu eventually agreed to impose a 10-month partial freeze that, among other loopholes, exempted building in East Jerusalem. Palestinians, their national movement now politically divided between secular nationalists and Islamists, view Jerusalem as the capital of their future state. Palestinian leaders did not join the U.S.-brokered peace negotiations until the final month of Netanyahu's building moratorium, and those collapsed quickly afterward when the Israeli prime minister declined to renew the freeze. Biden on Monday sought to turn the page on those differences, speaking mostly about Obama's record in defense of Israel. He called on Israelis, Palestinians and Arab states to again take up peace talks that would result in the creation of a viable Palestinian state next to Israel. "It's going to require hard steps on both sides," Biden said. "But it's in all of our interests - Israel's interest, the United States" interest, the interest of the Palestinian people. We all have a profound interest in peace. To use an expression of a former president, Bill Clinton, we've got to get caught trying.