The world is on the cusp of the most profound shift in global power and influence in a century. Managing this calls for nothing short of a new international system, with a radical revision of existing institutions and patterns of doing business. It is a time for thinking big.

Over the weekend, leaders of the Group of 20 world economic powers gathered in Washington to consider a "Bretton Woods II" world financial architecture. The institutions created at Bretton Woods, N.H., two generations ago — the World Bank and the International Monetary Fund — served their purposes over the years, but they are inadequate for meeting the global financial challenges of the 21st century.

The G-20 summit made modest progress in addressing the immediate crisis, but it hardly touched the harder challenges of institutional reform.

The summit failed for two reasons. First, the mechanisms do not exist to regulate governmental financial institutions, much less non- or quasi-governmental institutions such as China's sovereign wealth funds. Second, leaders of influential countries such as China and India made clear their disinterest in participating in global institutions that are dominated by the Western powers. The immediate challenge of creating a "Bretton Woods II" might begin with the Europeans and Americans voluntarily relinquishing their cozy agreement to reserve the top IMF and World Bank jobs for themselves and proposing a revision of the voting weights at both institutions to give the rising economic powers a greater stake and role (and to oblige them to pay higher dues as well).

This would clear the way for a strengthening of IMF roles in gathering and disseminating financial information, developing enforceable standards and codes for banks and sovereign wealth funds, and enhancing surveillance of financial systems — internationally and in individual countries — in conjunction with central banks.

This does not go far enough, though. It is not just the global financial mechanisms but also the institutions governing trade, energy, the environment, development assistance and security that need to be overhauled.

When he takes office, President Obama should seize the "Bretton Woods moment" — the recognition around the world that a new global order needs to be fashioned — to articulate and develop a larger vision.

Tackling these problems piecemeal won't do it. The solution lies in a "global grand bargain" — loosely linked trade-offs whereby the United States and Europe give a bit on the Doha trade round and induce Brazil and India to follow suit, China takes steps to reduce carbon emissions and Russia undertakes to act as a reliable energy provider and promoter of nuclear nonproliferation.

Early breakthroughs may be possible in some areas, such as a deal on climate change that brings in China and India and creation of a global fund to begin weaning us from fossil fuels. But this new system is not a single negotiated settlement, treaty or institution but a flexible set of reciprocal concessions among a dozen or so key countries that would evolve step by step.

Many of the foreign policy problems the Obama administration will inherit carry more risks than opportunities. They do not lend themselves to grand new initiatives or foreign policy successes.

It is precisely in creating a new international order that the administration should show boldness and imagination. In their meeting Saturday, G-20 leaders agreed to gather again no later than the end of April. This offers Obama an ideal opportunity to begin refashioning the G-20 as a flexible forum for working out this grand bargain.

Robert Hutchings is diplomat in residence at Princeton University's Woodrow Wilson School and was chairman of the U.S. National Intelligence Council from 2003 to 2005. He wrote this commentary for The Washington Post.