Success in the past does not guarantee success in the future. But one thing does seem clear from the historical evidence: the American system, for all its often stultifying qualities, has also shown a greater capacity to adapt and recover from difficulties than many other nations, including its geopolitical competitors. This undoubtedly has something to do with the relative freedom of American society, which rewards innovators, often outside the existing power structure, for producing new ways of doing things; and with the relatively open political system of America, which allows movements to gain steam and to influence the behavior of the political establishment. The American system is slow and clunky in part because the Founders designed it that way, with a federal structure, checks and balances, and a written Constitution and Bill of Rights—but the system also possesses a remarkable ability to undertake changes just when the steam kettle looks about to blow its lid. There are occasional “critical elections” that allow transformations to occur, providing new political solutions to old and apparently insoluble problems. Of course, there are no guarantees: the political system could not resolve the problem of slavery without war. But on many big issues throughout their history, Americans have found a way of achieving and implementing a national consensus.

When Paul Kennedy was marveling at the continuing success of the American superpower back in 2002, he noted that one of the main reasons had been the ability of Americans to overcome what had appeared to him in 1987 as an insoluble long-term economic crisis. American businessmen and politicians “reacted strongly to the debate about ‘decline’ by taking action: cutting costs, making companies leaner and meaner, investing in newer technologies, promoting a communications revolution, trimming government deficits, all of which helped to produce significant year-on-year advances in productivity.” It is possible to imagine that Americans may rise to this latest economic challenge as well.

It is also reasonable to expect that other nations will, as in the past, run into difficulties of their own. None of the nations currently enjoying economic miracles is without problems. Brazil, India, Turkey, and Russia all have bumpy histories that suggest the route ahead will not be one of simple and smooth ascent. There is a real question whether the autocratic model of China, which can be so effective in making some strategic decisions about the economy in the short term, can over the long run be flexible enough to permit adaptation to a changing international economic, political, and strategic environment.

In sum: it may be more than good fortune that has allowed the United States in the past to come through crises and emerge stronger and healthier than other nations while its various competitors have faltered. And it may be more than just wishful thinking to believe that it may do so again.

But there is a danger. It is that in the meantime, while the nation continues to struggle, Americans may convince themselves that decline is indeed inevitable, or that the United States can take a time-out from its global responsibilities while it gets its own house in order. To many Americans, accepting decline may provide a welcome escape from the moral and material burdens that have weighed on them since World War II. Many may unconsciously yearn to return to the way things were in 1900, when the United States was rich, powerful, and not responsible for world order.

The underlying assumption of such a course is that the present world order will more or less persist without American power, or at least with much less of it; or that others can pick up the slack; or simply that the benefits of the world order are permanent and require no special exertion by anyone. Unfortunately, the present world order—with its widespread freedoms, its general prosperity, and its absence of great power conflict—is as fragile as it is unique. Preserving it has been a struggle in every decade, and will remain a struggle in the decades to come. Preserving the present world order requires constant American leadership and constant American commitment.

In the end, the decision is in the hands of Americans. Decline, as Charles Krauthammer has observed, is a choice. It is not an inevitable fate—at least not yet. Empires and great powers rise and fall, and the only question is when. But the when does matter. Whether the United States begins to decline over the next two decades or not for another two centuries will matter a great deal, both to Americans and to the nature of the world they live in.

Robert Kagan is a senior fellow in foreign policy at the Brookings Institution and a columnist for The Washington Post. A version of this essay appears in his 2012 book, The World America Made. The publication of this essay is supported by the Hertog/Simon Fund for Policy Analysis.