In the first months of the Obama presidency in 2009, Chuck Hagel, who had just finished two terms as a U.S. senator, went to the White House to visit.

So, President Obama asked, what do you think about foreign policy and defense issues?

According to an account that Hagel later gave, he told Obama: "We are at a time where there is a new world order. We don't control it. You must question everything, every assumption, everything they (the military and diplomats) tell you. Any assumption 10 years old is out of date. You need to question our role. You need to question the military. You need to question what are we using the military for."

Hagel also said, "Afghanistan will be defining for your presidency in the first term, perhaps even for a second term." The key was not to get "bogged down."

Obama did not say much but listened. At the time, Hagel considered Obama a "loner," inclined to keep a distance and his own counsel. But Hagel's comments help explain why Obama nominated his former Senate colleague to be his next secretary of defense. The two share similar views and philosophies as the administration attempts to define the nation's role in the transition to a post-superpower world.

This worldview is part hawk, part dove. It amounts, in part, to a challenge to the wars of President George W. Bush. It holds that the Afghanistan war has been mismanaged and the Iraq war unnecessary. War is an option, but very much a last resort.

So, this thinking goes, the U.S. role in the world must be carefully scaled back - this is not a matter of choice but of facing reality; the military needs to be treated with deep skepticism; lots of strategic military and foreign policy thinking is out of date; and quagmires like Afghanistan should be avoided.

The bottom line: The United States must get out of these massive land wars - Iraq and Afghanistan - and, if possible, avoid future large-scale war.

Although much discussion of the Hagel nomination has centered on his attitudes about Iran, Israel and the defense budget, Hagel's broader agreement with Obama on overall philosophy is probably more consequential.

If Hagel is confirmed, he and the president will have a large task in navigating this new world order. Avoiding war is tied directly to the credibility of the threat to go to war.

Hagel's experience provides two unusual perspectives. The first is as a former E-5 Army sergeant in 1968, which he has described as "the worst year of the Vietnam War." In summation, another Vietnam must be avoided.

The second is the Georgetown University class that he taught called "Redefining Geopolitical Relationships." He asks the class the basic question: Where is all this going?

For example, he has said that one result of the Iraq war has been to make Iran the most important country in the Middle East, and he worried that Iraq could become an Iranian satellite.

When I interviewed President Obama in the summer of 2010 for my book "Obama's Wars," his deeply rooted aversion to war was evident. I handed Obama a quotation from Rick Atkinson's World War II history, "The Day of Battle," and asked him to read it. Obama read:

"And then there was the saddest lesson, to be learned again and again . . . that war is corrupting, that it corrodes the soul and tarnishes the spirit, that even the excellent and the superior can be defiled, and that no heart would remain unstained."

"I sympathize with this view," Obama told me. "See my Nobel Prize acceptance speech."

I dug out the Dec. 10, 2009 speech. And there it was:

"The instruments of war do have a role to play in preserving the peace. And yet this truth must coexist with another - that no matter how justified, war promises human tragedy. The soldier's courage and sacrifice is full of glory ... but war itself is never glorious and we must never trumpet it as such. So part of our challenge is reconciling these two seemingly irreconcilable truths - that war is sometimes necessary and war at some level is an expression of human folly."

That is probably the best definition of the Obama doctrine on war. Applying such a doctrine in today's dangerous, unpredictable world will be daunting - but on these issues Obama seems to have found a soul mate.

Bob Woodward is an associate editor of The Washington Post. His latest book is "The Price of Politics." Evelyn M. Duffy contributed to this column.