The United Nations (UN) Secretary-General is currently preparing a new agenda for peace, which is expected to broaden the traditional framework of security as it relates to relations between nations. It will also include the notion of human security, which focuses on the well-being of individuals and communities. This human security framework integrates traditional peace and security approaches with the achievement of the sustainable development goals. However, human security is difficult, if not impossible, to implement when nations are at war when they continue to rely on the threat of force for their security, and when they continue to focus national resources on preparations for war. In order to succeed, a human security framework has to be complemented with a common security framework. This would ensure that the threat or use of force in international relations is replaced by diplomacy, conflict resolution and international law, liberating resources for sustainable development. This common security framework works well when nation-states adhere to it. However, what happens when powerful countries, especially the nuclear-weapon states flout the law, ignore common security approaches to a conflict, and take aggressive military action? Since the end of the Cold War, this has happened a number of times, most notably the United States-led invasion of Iraq in 2003 and the Russian invasion of Ukraine in 2022. This article focuses on opportunities for states and civil society to make more effective use of existing common security mechanisms and strengthen common security through upcoming UN Summits. This could help to prevent war, phase out the reliance on nuclear deterrence, and shift national resources from militarism to human security, facilitating the achievement of sustainable development goals.