"The question we face is not whether America will lead, but how we will lead, not just to secure our peace and prosperity, but also to extend peace and prosperity around the globe."
So said President Barack Obama during a recent speech on the future of US foreign policy.
Though some, both inside and outside the United States, are happy to see America do less, others might be glad to hear him promise to continue to provide the leadership that only a global superpower can. Only a leader can enforce the rules, force the compromise, and underwrite the security on which geopolitical and economic stability depends.
This is a crucial issue, because today there is no government, or durable alliance of governments, ready to fill the vacuum if America retreats. Europe was focused on managing change within the euro zone even before parliamentary elections revealed growing public frustration with European governance.
China and Japan are fully occupied with risky domestic reform plans. Other emerging powers - India, Brazil, Turkey and others - are likewise busy with problems at home. All these countries can help, but none of them can lead.
But whatever Mr Obama tells a cheering crowd, there are several factors limiting Washington's ability to take on new challenges in places such as Ukraine, Syria, the South China Sea and cyberspace.
First, political leaders in most major developing states know they will still be in power long after the departure of Mr Obama. He will also wield much less influence in Washington as soon as Mrs Hillary Clinton and a few high-profile Republicans announce their candidacy for president. That will happen no later than next spring. This makes foreign leaders less willing to risk domestic political popularity by supporting the plans of the Obama administration.
Second, Washington continues to damage America's international reputation. The country's political polarisation has undermined confidence in Mr Obama's ability to deliver on his promises. The US use of drones has undermined relations with some allies, and Mr Obama's tolerance for (or ignorance of) US spying - including on the leaders of friendly governments - has alienated even more of them.