The 80th anniversary of the United Nations coincides with the 20th anniversary of the G4 (Brazil, Germany, India, and Japan), and with a deepening crisis of multilateralism. While the UN80 Initiative has launched reforms to address the UN's budgetary crisis, it has left reform of the UN Security Council untouched. Conversely, the G4 has focused almost exclusively on enlarging and legitimizing the Security Council, with little engagement in the broader reform agenda. After two decades it is clear that advancing their goals will require the G4 to demonstrate leadership in strengthening multilateralism more generally. The G4 emerged in 2005, amid the post-Iraq paralysis of multilateral institutions and declining trust among major powers. Like other ad-hoc coalitions it reflected hopes that flexible, informal arrangements could inject energy into a stagnant system. Yet concerns remain that exclusive clubs risk weakening the universal institutions they seek to support.