As is perhaps appropriate, the press, the pundits, and our political leaders often turn at this time of year to Dr. Martin Luther King, Jr.'s "I Have a Dream Speech" as the touchstone of discussions of his life and work. So it has been with President-elect Barack Obama, who presided over a concert and celebration of freedom at the Lincoln Memorial last night -- the site of the "I Have a Dream Speech," given at the 1963 March on Washington.

One passage from that speech rings particularly true today: "We have also come to this hallowed spot to remind America of the fierce urgency of Now. This is no time to engage in the luxury of cooling off or the tranquilizing drug of gradualism. Now is the time to make real the promises of democracy." The extent to which we move with urgency to make those promises real will be a measure of the Obama presidency, and of our ability as a nation to seize this historic moment.

But it is important to remember that Dr. King's thought extended beyond the notion of equality under law to embrace economic justice at home and abroad. In his April 4, 1967 speech at Riverside Church -- delivered one year before he was killed in Memphis -- King not only denounced the war in Vietnam in no uncertain terms, but he spoke directly to the need to change the role of the United States in the world. On the home front, he said that "I knew that America would never invest the necessary funds or energies in the rehabilitation of its poor so long as adventures like Vietnam continued to draw men and skills and money like some demonic destructive suction tube." So it is today in Iraq, which has driven U.S. military spending higher than it was at the peak of Vietnam, even as poverty rates climb and more people fear for their homes and their jobs every day.

But King went further -- it wasn't just that imperial adventures soaked up funds that could be used in America. It was also necessary to get on the right side of history with respect to changing the relationship between the "developing" (to the extent that it is or was developing) and the developed world: "I am convinced that if we are to get on the right side of the world revolution, we as a nation must undergo a radical revolution of values. We must rapidly begin the shift from a 'thing-oriented' society to a 'person-oriented' society. When machines and computers, profit motives and property rights are considered more important than people, the giant triplets of racism, materialism, and militarism are incapable of being conquered." While efforts are being made by some leaders in Congress to right the imbalances, one need only look at who is getting the bulk of the funds from the federal bailout to see that profits and property rights are still being honored at the expense of people in need.

While the rhetoric of revolution has faded with the disappointing developments in many of the nations that gained independence in the great nationalist upsurge of the 1950s and 1960s, we are still faced with many of the same problems posed by those movements -- giving people the material wherewithal and the political freedom to pursue their destinies without being bound by hunger, disease, and repression. There has been progress, but we have a long way to go down that road before we can say that justice has been done. So, a second challenge for America under the leadership of an Obama administration is to contribute not only to economic recovery at home, but to promoting economic justice around the world.

The politics of seeking the kind of change that Dr. King spoke of so eloquently depend upon active social movements. The line between "tranquilizing" gradualism and "fierce urgency" depends on what people demand, not just on what government chooses to deliver. Obama has spoken many of the right words, but to do the right thing he will need our help, as he himself has acknowledged. The content of "change" depends on us, not just on Barack Obama.