Foreign policy achievements have thus far stood out for their absence during President Obama's tenure. The engagement with Iran, the "reset" of relations with Russia, the intermediation in the Israeli-Palestinian conflict, the protestations against cyber-attacks coming from China against U.S. firms, the pressures on North Korea and the "red line" warnings to the Syrian regime over chemical weapons, have all failed to advance peace or democracy in the world or to strengthen the American hand in international relations.
U.S. foreign policy initiatives have, in no small measure, been subordinated to the acquiescence of the UN Security Council, where they are toned down to the point of innocuousness in order to circumvent the veto of rivals Russia and China.
True, this administration can boast about the execution of bin Laden and a considerable number of other prominent terrorists, but progress in this area belongs more to the realm of intelligence and military sophistication rather than to foreign policy, per se.
The question arises as to whether the limits of President Obama's foreign policy are the result of a faulty but corrigible diplomacy, or rather, the consequence of an irreversible waning of U.S. leverage in world affairs.
For starters, it is worth recalling that the U.S. experienced a similar predicament during Jimmy Carter's presidency. At that time, America's foreign policy was neither more coherent nor more forceful than that of its strategic rival, namely Leonid Brezhnev's Soviet Union.
While Jimmy Carter was entangled in the Iran hostage crisis and grappled with stagflation, the Soviet Union was invading Afghanistan, enlarging its presence in Africa with the help of Cuban troops and crushing dissent in Eastern Europe.
Yet, a few years later, the U.S. carried off the Cold War contest.
Such an outcome proves that having a forceful foreign policy is no guarantee of success, and, conversely, that a feeble diplomacy would not by itself toll the knell of a hegemon.
In the fight for geopolitical preponderance, superiority in certain fundamental domains -- notably the economy and technological and military sophistication -- play a more decisive role than diplomatic might.
And it so happens that, after the Carter years, America's free market economic vitality managed to overcome stagflation and expand its technological lead at the same time as the Soviet centrally planned economy continued in the path of self-asphyxia.
In protecting and consolidating preponderance, equally important is the system's ability to question itself and correct its own failures.
Here, too, America demonstrated its competitive edge vis-à-vis the USSR. Carter's foreign policy flops were so impairing that they became an issue in the 1980 presidential contest. Free elections gave Americans the opportunity to send an assertive Ronald Reagan to the Oval Office. Meanwhile, the rigidities inherent in one-party systems led to the demise of the Soviet bloc, despite Mikhail Gorbachev's attempts to reform and salvage it.
That said, there are geopolitical configurations in which foreign policy does determine the course of events. The narrower a hegemon's preponderance in the aforementioned fundamental domains is, the more it will depend on a punchy diplomacy to prevail over its challengers.