The great national security threat of the past decade was terrorism. Certainly, the threat remains very real and very dangerous, as we were reminded this weekend. But we must pay attention now to the next national security threat: the drive, led by an increasingly right-wing Republican Party and fueled by the ill-informed Tea Party movement to force America to withdraw from the world. We ignore it at our peril.

Al Qaeda is on the run, and Islamic extremism has failed to gain significant footholds across the globe beyond the failed, failing, and dysfunctional states of Yemen, Somalia, Pakistan, and Afghanistan. We face tough challenges in those countries, and addressing them will take longer and be more difficult than we had hoped. But we are making progress.

Perhaps the best news is the complete insignificance of Al Qaeda in the dramatic revolutions sweeping much of the Arab world. Why has Al Qaeda been absent? Because its leaders failed to address the concerns of the majority of Arabs. People are not buying what Al Qaeda is selling. The citizens of Tunisia, Egypt, and Libya don’t hate America—they hate their own broken and repressive governments that failed to adhere to the basic tenets of prosperity.

But the protests have also revealed a disquieting truth about America: We may not be hated, but we, too, were irrelevant to the Arab Spring. Indeed, if Al Qaeda defined our challenge in the last decade, our struggle in the coming ones will be to once again get ahead of the curve on what the world wants from America: stalwart, good-faith leadership to help the rest of the world achieve prosperity.

For too long, we have been out of touch with the desires of the vast majority of the world’s people. Because of technology, people can now see others living a prosperous and free life. They can now also see past the propaganda their leaders use to justify their failures. What they don’t see is an America leading the world in solving the problems they face.

Our recent support of the Libyan people has been important for precisely that reason. The Arab world saw an America mobilizing the international community to stop a dictator who announced that he would go house to house to kill citizens. But our responsibility should not end with the overthrow of Gaddafi. The Arab world must see an America galvanizing robust aid to the Arab people as they seek to build more secure, just, and prosperous societies.

We don’t have to—and indeed, we shouldn’t—take up this task on our own. But we must lead in ensuring long-term global support for the development of institutions and laws that will guarantee them a better life. That means the United States must once again become the world’s great persuader—not just in rebuilding after the Arab Spring but also in meeting today’s broad global challenges. Even in these economically difficult times, the U.S. must use its full political, moral, economic, and, at times, military weight to come up with solutions to the world’s challenges: climate change, nuclear proliferation, global food and water crises, the spread of infectious disease, human rights violations.

Many Americans don’t see why we should make these issues our priorities. But hampering America’s ability to lead by slashing foreign aid and cutting back on our diplomacy in a mad rush to cut the deficit—as conservatives want to do—is simply foolish. Too often, only our own economy, hot-button social issues, and the next terrorist attack grab hold of the American psyche. But unless we lead the world in developing responses to its challenges, we won’t have the rest of the world on our side when we need to solve our challenges.

But to restore America’s global leadership, we must first combat the domestic forces that seek to rein in that role. As we head into the 2012 presidential elections, progressives in government and out will need to explain to the American people what is at stake and how combating instability abroad is key to America’s national security. Convincing Americans that our prosperity depends on our promoting the prosperity of the world will be a tough challenge. But if we succeed, it will be our lasting legacy.