Washington must assert to the rest of the world that if they want to be friends with America, they need to do more to keep Iran from acquiring nuclear weapons, visiting US Speaker of the House Nancy Pelosi said Sunday in an exclusive interview with The Jerusalem Post. Pelosi said the US needed to be more "proactive" in saying to the countries of the world - including Russia, China and the Muslim countries in Asia - that "one of the pillars of US foreign policy is to stop the proliferation of weapons of mass destruction to anyone." The US needed to make it clear to everyone, including the Europeans, that their polices on this issue would be a term of friendship with the US, and a measuring stick of benefits they could derive from that friendship, she said. The US cannot stop nuclear proliferation alone, Pelosi said, adding that "if these weapons proliferate, they are a threat to everyone, not just to the US, and not just to Israel." The Democratic Pelosi, the No. 3-ranking politician in the US after the president and the vice president, is leading a blue-ribbon panel of 13 congressmen to Israel for the state's 60th anniversary. The group arrived Friday and is scheduled to leave Monday evening after meeting the gamut of Israel's leaders, including President Shimon Peres, Prime Minister Ehud Olmert, Defense Minister Ehud Barak, Foreign Minister Tzipi Livni and opposition leader Binyamin Netanyahu. Pelosi said that to stop Iran's nuclear march, short of a military strike - something she did not rule out as a last resort - "you have to go all the way. And people have to know you are deadly serious that if you want to be our friend, if you want the benefit of our friendship, a central pillar of our foreign policy is to stop the proliferation of weapons of mass destruction." This can't just be a "conversation," she said, "it has to be seriously enforced and sanctioned, because the alternative is one that has a tremendous downside - and that would be to use military force." While saying that a military option should not be taken off the table, and adding that an attack by Teheran on Israel certainly "cannot go unanswered," Pelosi said that a preemptive strike on Iran would have consequences that needed to be considered. Among the consequences she listed were the effect such an attack would have in rallying Iranians around their current leadership, what it would do to the price of oil, and the response of the rest of the Muslim world. Pelosi refused to get drawn into a discussion of whether US President George W. Bush was wrong in insinuating during his Knesset speech last week that Democratic presidential hopeful Sen. Barack Obama would appease the Iranians, saying that she would not criticize the president on foreign soil. Before leaving Washington, however, she said that Bush's characterization was "beneath the dignity of the office of president." Pelosi did say here that she was confident Obama would deal squarely and assertively with the Iranian dossier. "I know that Barack Obama would meet the challenge we have in terms of Iran," she said. "And he may do it in a larger way. I don't know how you define strength here, but in the US we define it not only in terms of our military might, and our willingness to use it - that's important - but we define it in terms of our values, where we can attract others to a place where we can keep the peace without making war, but without taking war off the table." Pelosi said Obama was "a real leader, and to be a real leader you have to be prepared to fight in order to make peace, and I think he is prepared to do that." As to whether Obama would be as supportive of Israel as Bush has been, Pelosi said, "I think a Democratic presidency would be very supportive." She said she didn't know how to measure Bush's support. "I know people here think he has been very supportive, [but] we don't have peace yet. I hope under a Democratic president that we would." During a meeting with Peres earlier in the day, Pelosi said Israel was an issue and a value that brought Democrats and Republicans together. "We owe you a great deal of gratitude," she said, "because in resisting weapons of mass destruction, Israel was not only looking after her own security interests but those of the rest of the world." Referring to the Jewish state as a beacon of democracy, she said that Israel and the US shared the same vision of the future. On a more personal note, Pelosi - the first female House speaker - told Peres, "We always knew you'd be president, but I didn't know that you would welcome me as the speaker of the House." The other members of the visiting delegation are House Majority Leader Steny Hoyer of Maryland, Republican Conference Chairman Adam Putnam of Florida, Caucus Chairman Rahm Emanuel of Illinois, Democratic Caucus Vice Chair John Larson of Connecticut, Oversight and Government Reform Chairman Henry Waxman of California, Foreign Affairs Committee Chairman Howard Berman of California, Rules Committee Ranking Member David Dreier of California, Foreign Affairs Middle East Subcommittee Chairman Gary Ackerman of New York, Appropriations Foreign Operation Subcommittee Chairman Nita Lowey of New York, Commission on Security and Cooperation in Europe Chairman Alcee Hastings of Florida, Homeland Security Intelligence Information Sharing and Terrorism Risk Assessment Subcommittee Chair Jane Harman of California and Foreign Affairs Committee member Ron Klein of Florida. Greer Fay Cashman contributed to this report.