Viewpoint: Obama carefully preserves US power
Republican presidential candidate Mitt Romney has accused President Barack Obama of overseeing the decline of America's standing in the world. But Mr Obama's substantial national security track record shows he preserves American might by wielding it carefully.
Although voters say the economy is foremost on their minds ahead of November's election, developments in Iran, Syria and the eurozone could easily become political wild cards.
And Mr Obama's national security record includes meaningful accomplishments that hint at how he might handle them.
On his watch, the US eliminated Osama bin Laden and is nearing the strategic defeat of al-Qaeda. The US has increased political and economic pressure on Iran, ended the Iraq war and begun shifting US engagement in Afghanistan.
It has renewed the Non-Proliferation Treaty and ratified a new strategic arms treaty with Russia, strengthened the US posture across Asia while managing the complex relationship with China, and ushered a new country, South Sudan, onto the world stage.
Mr Obama has also had his share of misses.
He failed to close Guantanamo Bay, though his pledge to do so in large part earned him a Nobel Peace Prize. Climate change has virtually disappeared from the administration's political agenda. The Middle East peace process has stagnated despite a substantial political commitment.
Mr Romney discounts Mr Obama's record as one of American leadership in decline. He portrays engagement as apology, and caution as confusion.
But Mr Romney surely knows that interests and values compete as often as they coincide.
Even his idol Ronald Reagan struggled to square actions and ideals. The deployment of Marines into the middle of the Lebanese civil war in 1983, the Hezbollah attack on their barracks that killed 241 troops, and the subsequent retreat reflect the challenge.
In the aftermath, Reagan's Secretary of Defense Caspar Weinberger advanced a "doctrine" to guide the future deployment of US forces.
Military forces should be committed as a last resort only when vital interests are at stake, when they can achieve clear political and military objectives, and when they have the backing of Congress and the American people.
Iraq's excessive costs
Colin Powell, then chairman of the joint chiefs of staff, America's top uniformed military officer, further refined US thinking after the 1991 Gulf War.
He suggested that all risks, costs and consequences be considered before intervening, that overwhelming force be employed to attain the stated objectives, that there be an exit strategy, and that action have not just domestic but also international support.
In Iraq, George W Bush violated most tenets of the Weinberger and Powell doctrines. He failed to attract meaningful international support for the 2003 invasion, failed to integrate military and political objectives, and failed to anticipate the rise of Iran after Saddam Hussein's fall.
And for what the conflict did achieve, the US paid excessive costs in blood, treasure, and international standing.
Mr Obama's military actions - ending the Iraq war, establishing an exit ramp for Afghanistan, intervening in Libya but not in Syria - do not represent a new doctrine. Rather, they reaffirm and further refine the logic behind the use of American military force that has influenced, if not strictly guided, US presidents in their military interventions since Vietnam.
Meaning of leadership
Mr Romney sees American leadership in zero-sum terms: If America fails to lead, someone else will. That formulation fit the bipolar competition of the Cold War but is less relevant in today's interconnected and globalised world that lacks an overarching threat.
Mr Obama views leadership in positive-sum terms. US leadership is enhanced and renewed when exercised within alliances and dynamic partnerships and with emerging regional powers that can solve shared problems and help shoulder political and economic costs.
The president's deliberate approach is not about doubt or decline, but the preservation of US leadership following a period in which it was recklessly spent.
He ended the Iraq war because the US had done all it could. He is winding down the conflict in Afghanistan because it is no longer central to the ill-defined war on terror, which he recast as a more achievable war on al-Qaeda.
He has relied more significantly on drones to accomplish his state goal to "disrupt, dismantle and defeat al-Qaeda" expressly because they are effective and avoid the significant economic and political costs of large-scale invasions and occupations.
Balance in Libya
In some respects, Libya is a model for Mr Obama's thinking: a limited intervention with strong regional support, backed by a UN Security Council resolution that provided legality and legitimacy and willing partners.
Republicans have made hay of "leading from behind," a description of Mr Obama's Libya policy attributed to an unnamed administration official. But the fact is Libya was far more important to Europe and the Arab League states than to the US.
Mr Obama's commitment was appropriately balanced against the mission's costs, benefits, risks and likelihood of success.
But Libya's success has come at the expense of effective action in Syria.
Unlike with Libya, Russia and China can be expected to block any consensus for military action that might lead to regime change in Syria.
The Syrian opposition is fractured, the region divided and Nato distracted. The president's lofty rhetoric regarding the Arab Awakening has been grounded by the grim reality of the Syrian civil and proxy war.
While Mr Obama has called for Bashar al-Assad to step down, he has not invoked a responsibility to protect the Syrian people as he did in Libya.
'World as it is'
The administration continues to weigh military options regarding Syria, but it does not yet see one that can be effective at an acceptable cost. The Libyan model is not likely to be repeated.
This tension between universal ideals and what Mr Obama has termed the "world as it is" can never be completely resolved.
Both presidential candidates believe in American exceptionalism. But once a candidate takes office, his hope is tempered by the real world of expanding challenges and finite resources.
And the real world cannot be easily or economically transformed.
PJ Crowley is a former US assistant secretary of state under President Obama and is now a professor of practice and a fellow at the Institute for Public Diplomacy and Global Communication at the George Washington University.