The world’s systems of international cooperation are facing three great conflicts at once: violent conflict in Ukraine, political conflict between great powers, and a fissure between the near-term priorities of the world’s rich and powerful societies and the long-term needs of both poorer societies and the planet itself. The first two conflicts exacerbate the third. Amid massive investment shortfalls, the global sustainable development agenda is on the brink. Next year, 2023, will mark the midpoint to the Sustainable Development Goal deadline of 2030. It’s high time to start preparations for a better “second half” of the SDG era. The G7 needs to be a two-pronged leader, one that lends all its supportive muscle to mobilize required forms of capital while also leading through the power of its own influential example. Three deep structural changes over the past two decades have shifted the context for G7 contributions: (1) the smaller relative power of G7 countries on the global stage, (2) the more complex and fragmented policy terrain, and (3) the flawed heritage of high-profile G7/8 commitments. Amid the world’s deep practical interconnections between the “infrastructure agenda,” the “climate agenda,” and the “sustainable development agenda,” all G7 countries need to prioritize their domestic implementation of the SDGs. In parallel, they need to help mobilize a massive scale-up of public and private resources for global sustainable development. This includes partnering with other countries to instigate profound changes in the scale and business models of the multilateral development banks, while also taking a leadership role to promote SDG alignment in public and private financing systems. G7 efforts relating to infrastructure should be pursued in the larger context of the 2023 moment for the SDGs and existing efforts coordinated through the G20 and elsewhere. The G7 can further consider a range of proposals to boost a partnership-driven approach to international cooperation on specific issues.