LETTER FROM EUROPE – Finding the Limits of U.S. Power

PARIS — The language may have softened, but in the realpolitik of the nuclear debate, the hard choices remain.

In some of the same lands described by President George W. Bush as an axis of evil, the Obama administration confronts an arc of obduracy from Pyongyang to Tehran. The riddle persists for the new administration as much as a solution eluded its forerunner: how can America change the bellicose behavior of those who do not wish to be changed, least of all at Washington’s behest?

In military terms, Iraq, one span of the Bush-era axis, where nuclear weapons were not found, is giving way to Afghanistan as the prime test of a president’s military resolve, all the riskier with troops deployed on two far-flung fronts.

But, diplomatically, the unfinished business lies in North Korea and Iran — twin beacons of nuclear ambition casting a baleful, contrary light onto the frontiers of America’s ability to impose its will on those who see nuclear technology as a portal to respect and influence that would otherwise elude them.

And perhaps, in a backhanded way, the real puzzle lies not so much in America’s deployment of power as in the acknowledgment of its limits.

Last Sunday, Vice President Joseph R. Biden Jr. vouchsafed that “the United States cannot dictate to another sovereign power what they can and cannot do.” He was referring to the question of whether Washington would restrain Israel from a military strike at Iranian nuclear facilities, and his remarks may have been no more than a casual misstatement, soon disowned by the White House.

But Mr. Biden’s nostrum raised a possibly mischievous question: if Washington does not feel able to restrain its friends, what can it hope to achieve with its enemies?

Visiting Moscow this week, President Barack Obama spoke of those same interlocking themes of power and sovereignty.

“In 2009, a great power does not show strength by dominating or demonizing other countries,” he said. “The days when empires could treat sovereign states as pieces on a chess board are over.” So much for the New American Century that neo-conservatives believed would become an era of untrammeled power after the decades of ideological and military competition with the Soviet Union.

The Cold War, of course, was terrifying — massed armies in Europe; nuclear arsenals; the Strangelove equation of mutually assured destruction: wipe out Washington, and Moscow goes, too. Incinerate London and bid farewell to Leningrad. But it was not all about confrontation.

By assuming a balance of nuclear power, the Cold War held much of the planet in check. With some dramatic exceptions, policy makers in Washington and Moscow knew whom to call to put out the brushfires before — sometimes just before — they became infernos.

But, beyond the nuclear arsenals, the notion of parity was always flawed. In so many ways, Moscow was not the economic, political or social equal of the United States. And, 20 years after the crumbling of the Soviet empire, that imbalance has not been redressed any more than diplomacy has devised a new set of global rules.

“What kind of future are Russia and America going to have together?” Mr. Obama asked in Moscow. “What world order will replace the Cold War? Those questions still don’t have clear answers.”

In other words, who will police the planet at a time when the nuclear debate entwines worries about terrorism and the resurgence of what was once described as a crescent of crisis stretching from Afghanistan and Pakistan through Iran and the Gulf to the Horn of Africa?

Arguably, Mr. Obama is seeking a return to an older equilibrium after the roller-coaster years of Russia’s economic turmoil in the 1990s and its bullish nationalism under Vladimir V. Putin — a partnership, he said, that “will be stronger if Russia occupies its rightful place as a great power.”

Indeed, without the support of Russia and China in the international politics of nuclear enforcement, the United States cannot hope for the leverage it needs to pressure Pyongyang or Tehran.

“If we fail to stand together” to press for nuclear nonproliferation, Mr. Obama said in Moscow, “international law will give way to the law of the jungle.”

But there are many dark holes in the calculation.

By ALAN COWELL, nytimes.com