The G-8 summit in St. Petersburg this week takes place against the backdrop of growing warfare and anarchy around the world. The attacks from Gaza and Lebanon have reignited the ongoing war against Israel while chaos and violence escalate in Iraq and the nuclear weapons programs of Iran and North Korea threaten the core security and economic interests of the major powers. The failure of the United Nations in confronting rogue states and terror groups has been a major aspect of the post-Cold War era. Instead of the responsible, moral and effective leadership promised in 1945, the UN is mired in corruption, an absence of leadership, and an anti-democratic majority that has destroyed its legitimacy. The UN's "accomplishments" on terror and Iran speak for themselves. Peace-keeping efforts in different parts of the world (including around Israel's borders) show few successes, and the UN Human Rights Commission (now replaced by a similarly flawed Council) has led the degradation and political exploitation of human rights. As a result, the focus and the hopes for some reduction in the anarchy have shifted to the G-8. This group of major economic and political powers, which now includes Russia (and may soon add China), has been assuming many of the tasks assigned to the United Nations, and particularly to the Security Council. TO SUCCEED, a new international structure based on the G-8 cannot be another impractical attempt at world government, but must rather be a realistic mechanism for preventing massive destruction and anarchy. Conceptually, an expanded G-8 framework, based on intensive consultation and cooperation, might be compared to the 19th-century "Concert of Europe," which did a reasonable job of preventing a repetition of the chaos and destruction unleashed by Napoleon and balancing the vital interests of the major powers. Instead of destructive zero-sum strategies, policies based on realism and responsibility prevented additional wars, including those fought in the name of religion that had devastated Europe for centuries. When the Concert collapsed, the result - in the form of two world wars - was catastrophic. Structurally, the G-8, like the Concert, is based on a small number of actors representing the major status-quo powers. Of course, there are many aspects of 19th-century European diplomacy that should not be transferred to the G-8 framework, such as the colonialism and imperialism that supported the balance of power. And while democratic values and human rights principles were largely absent (contributing to the collapse of the Concert and the explosion of World War 1), these norms are central to the 21st century. To gain the moral legitimacy the UN has squandered, all the members of the G-8, including Vladimir Putin's Russia, need to promote democratic values. On the basis of this structural and normative foundation the G-8 framework can and should develop policy frameworks to deal with the central issues and threats - particularly with respect to Iranian nuclear weapons. The security of all of the members of the G-8, including Russia, is threatened by a radical Iranian regime armed with nuclear weapons. IN CONTRAST to the gridlock at the UN, the G-8 is able to act quickly, responsibly and effectively on Iran. The first stages of G-8 involvement in this issue have been taken in previous meetings, and the ministerial working group meetings have expanded the level of consultation, but without tangible results. The Russian leadership, which has been demanding concessions regarding Ukraine and in other areas in return for cooperating in confronting Iran, must now decide whether it will take the responsibilities of a world power seriously. The St. Petersburg summit may be the last chance to develop a clear and coordinated policy necessary to halt Iran's effort to acquire nuclear weapons. And a serious approach to Iran, including sanctions, would also echo in North Korea. A unified G-8 policy on Iran would, moreover, spill over in promoting stability and reducing the level of violence against Israel. The Iranian regime has become the primary source of terror attacks against Israel, and the close relationship was underlined by Hamas head Khaled Mashaal's visit to Iran, the rhetoric of genocide and the pledges of financial support. Recent crises between India and Pakistan, which came very close to nuclear destruction, highlight the dangers from the mix of terrorism and nuclear-armed sponsors. Similarly, Iran's close links to Hamas and Hizbullah could easily ignite a full-scale confrontation. On these and other issues, the G-8 - as the institutional embodiment of the responsible world powers - has a narrow window in which to act responsibly, not as a supplement to the discredited UN, but as a replacement. The writer is the director of the Program on Conflict Management at Bar-Ilan University and the editor of NGO Monitor.