When he took office in 2009, Barack Obama immediately became a war president, a two-war president in fact. The terrorist attacks of 9/11 had made that inevitable.

Yet it seemed an unlikely role. He had been a constitutional law professor and community organizer who had never served in the military. During his brief time in the US Senate, he served as a junior member on the Foreign Affairs and Veterans’ Affairs committees, but military issues were not his specialty.

Consider one difference with his immediate predecessor in the White House: Though he’d cut short his time in the Texas Air National Guard and never served overseas, former president George W. Bush had easily transferred his Texas persona to a “mission accomplished” swagger across an aircraft carrier flight deck. Obama would have looked as out of place there as Michael Dukakis did in a US Army tank during his failed 1988 presidential bid.

RECOMMENDED: How 9/11 has shaped a generation of Americans

Yet in his 32 months as president, Obama – a Nobel Peace Prize winner – has embraced the role of commander in chief of the most powerful military in human history.

While winding down the war in Iraq, he has escalated the war in Afghanistan – extending that into Pakistan (and likely other countries) through a steep increase in Predator drone attacks on Al Qaeda figures. On the ground there, US military casualties per year have more than tripled since he took office. (Yesterday, a massive Taliban truck bomb outside a combat outpost wounded 77 NATO soldiers, most of them Americans.)

When some advisors urged a more cautious approach to confirmed intelligence that Osama bin Laden had been located in Pakistan, Obama chose the riskier option of sending Navy SEALs to do the job – a mission that might have been as disastrous as the attempt to rescue the American hostages in Iran in 1980.

His response to the uprising in Libya was measured – US naval and air forces led the way in pounding Muammar Qaddafi’s military, while American ground forces were ruled out – but in retrospect that seems to have been correct.

Terror threats remain, as this weekend’s heightened security in New York and Washington showed. But largely because of the administration’s use of armed drone aircraft and Special Forces units, Al Qaeda is "on a steady slide," White House counterterrorism chief John Brennan told the Associated Press recently.

"If they're worrying about their security … they're going to have less time to plot and plan," Brennan said. "They're going to be constantly looking over their shoulder or up in the air or wherever, and it really has disrupted their operational cadence and ability to carry out attacks."

Obama’s aggressiveness at war has been a surprise to many, especially to a liberal base that had heard him speak at antiwar rallies. Yet even then, he made it clear that he was not a pacifist.

“What I am opposed to is a dumb war,” he had said at one such rally in Chicago in 2002, referring to the Bush administration’s impending decision to invade Iraq. “What I am opposed to is a rash war. What I am opposed to is the cynical attempt by … weekend warriors in [the Bush] administration to shove their own ideological agendas down our throats, irrespective of the costs in lives lost and in hardships borne.”

But Obama also emphasized that he did not oppose all wars.

“After September 11th, after witnessing the carnage and destruction, the dust and the tears, I supported this administration’s pledge to hunt down and root out those who would slaughter innocents in the name of intolerance,” he said at the same rally, referring here to Afghanistan. “And I would willingly take up arms myself to prevent such tragedy from happening again.”

Years later, and after what critics say was the Bush administration’s failure to follow up on Afghanistan, Obama did take up arms in going after the Taliban and Al Qaeda– this time as commander in chief.

Looking back, writes Washington Post foreign affairs columnist David Ignatius, “It’s an interesting anomaly of Barack Obama’s presidency that this liberal Democrat, known before the 2008 election for his antiwar views, has been so comfortable running America’s secret wars.”

Given his record as president, Obama – if he had served – likely would have been attracted to the intelligence services or special operations, according to this analysis.

“Intelligence is certainly an area where the president appears confident and bold…. This is a president, too, who prizes his authority to conduct covert action,” Ignatius writes. “He likes making decisions in private, where he has the undiluted authority of the commander in chief. He likes information, as raw and pertinent as possible, and he gets impatient listening to windy political debates. He likes action, especially when he doesn’t leave fingerprints.”

Even if he’s not re-elected, Obama’s fingerprints certainly will be on the history of how the United States conducted itself in the wars that continued ten years after 9/11.

RECOMMENDED: How 9/11 has shaped a generation of Americans