WHEN THE LEADER OF THE FREE WORLD LEADS…. President Obama’s Nuclear Security Summit is ongoing in Washington, with the U.S. president playing host to 47 world leaders in “the largest gathering of world leaders arranged by a U.S. president since FDR set up the 1945 meeting leading to the United Nations.”

On some fronts — including progress with China on Iranian sanctions and a Ukrainian decision on highly enriched uranium — it appears that the summit is already paying “early dividends.”

The New America Foundation’s Steve Clemons takes this further, praising Obama’s “calculated subtlety and strategic depth.”

Obama is changing the direction of global gravity. He is also confronting Iran without the shallowness of bombing vs. sanctions vs. public humiliation that his administration has been flirting with. In the past week, and over the next month, Obama is showing what a U.S.-led world order should look like.

This is a huge shift, for the world hasn’t had much faith in America’s abilities to deliver. For example, in taking on strategic challenges like getting the Israelis and Palestinians on a two-state pathway; or ending the anachronistically simmering Cold War conflict in U.S.-Cuba relations; or persuading Iran to forgo a nuclear weapons track, most of the world has seen an America unable to achieve the objectives it sets out for itself.

In recent years, this has translated into a sense that the United States is a well-branded, globally important but underperforming country, whose influence is weakening — more like a national version of General Motors than Google.

Now, out of the blue, Obama is changing the game.

A lot of developments have unfolded very quickly, starting with the breakthrough on a new arms treaty with Russia, followed by the Nuclear Posture Review, followed by this week’s successes during the Nuclear Security Summit. The result, Clemons noted, is a White House “mending the foundation and infrastructure of a global nonproliferation regime” Republicans of the Bush/Cheney era “worked hard to tear down.”

Obama has now showed two essential strengths. First, he can deliver what he promised in September 2009, when he chaired a special Security Council session. Second, his team understands the difference between approaches that have strategic depth and can move global players into new positions versus those that are vapidly bilateral and uncompelling to either party…. Obama and his team are finally showing a Nixonian deftness for creating new possibilities at just the time the world believed America was a global has-been.

In a political context, I realize this isn’t the kind of thing that will give Obama a bump in the polls. The vast majority of Americans almost certainly won’t even hear about the president’s deft leadership on the nuclear front. But history will likely recognize this as a time when the United States, at long last, began to reassert its leadership role on the global stage, making us safer in the process.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.