This is a story about friendship, unexpected evolutions, and stepping up to the plate.

But first a prologue: A few days before the attacks of September 11th, I was sitting at dinner in New York and the conversation stumbled on to the subject of courage, how our generation had never been taught to value it. Instead, our education system focused on the virtues of multiculturalism and the cultivation of individual sensitivity, but not the value of physical courage, of facing your fears and rising above them, doing the difficult thing because it is the right thing.

At the time, these seemed like lost values – out of place after the virtual millions made in the Internet boom of the late 1990s. But then the Towers fell and the first war heroes of the 21st century sprang fully formed from the fire houses of lower Manhattan and Brooklyn. The attacks redefined our generation, causing us look beyond the personal dramas and petty grievances of the Seinfeld era. We were all transformed, some more immediately and evidently than others.

This is the story of Matt Pottinger. Matty was like a brother to me in high school. We were in a band called Blind Dog Whiskey – Matt played keyboards – and talked endlessly about music, writing and girls, while laughing a lot at the expense of what we saw as hypocrisy or pretense. We spent far more time doubled over and dodging trouble than we did studying.

Nonetheless, around the marker of our 10th reunion, Matt Pottinger was an unlikely rock star of geopolitical journalism, one of the Wall Street Journal’s lead reporters in China, covering government machinations in Beijing and Hong Kong. We stayed in touch via e-mail, and would head out to dinner once a year when he came to New York. It was as if no time had passed – the laughter was free flowing and the conversation still rewarding, even as it moved on to broader horizons.

Three months ago, over lunch at The Oyster Bar in Grand Central, he told me he’d joined the Marines. This was an out-of-right-field revelation: Matt Pottinger had never been a rah-rah patriotic kind of guy. He was a clear-eyed skeptic. He never had a poster of Rambo on his wall; more likely it was Miles Davis. He wasn’t watching Top Gun, but movies like “Monty Python and the Holy Grail.” But Matt, like all of us, had been awakened by September 11. Unlike most of us, he stepped up and did something about it.

His decision was the crystallization of a dozen different experiences, all of which had deepened his sense of duty. In covering corruption in the Chinese government, he had been attacked by the secret police, seen people routinely intimidated, laws disregarded, brutalities ignored. He realized that this was how most of the world worked, and that the liberties we too often take for granted in the United States are the exception, not the rule, in human history.

One year ago, he covered the tsunami in Southeast Asia, saw bodies stacked up in piles inside Buddhist temples, and saw Marines save thousands of lives by delivering medicine and supplies in the crucial days after the tidal wave hit. They did not do it for the cameras and there was no press release. The U.S. showed up in force because it was the right thing to do. Contrast that with the televised terrorist executions that al-Zarqawi and his thugs were spreading around the world via the Internet and it was easy to take sides. Matt joined the Marines.

Never anyone’s idea of a linebacker, Pottinger started physically training in a way he hadn’t before. Perhaps more humbling (for both of us) was the fact that at age 32, he needed an age waiver to proceed.

Ten days ago, he graduated from the Marine Officer Candidates School in Quantico, Va. Last week, we went to a steakhouse on the Lower East Side to celebrate. His head was shaved but his eyes were alive, still driving on adrenaline. He explained the endless drills on little sleep and the professionalism of the instructors. He talked about the mental and physical discipline it takes to complete the training – how we’re all capable of much more than we can imagine – and he spoke with pride about the Marine tradition.

The day before graduation, Pottinger published a column on the Wall Street Journal editorial page describing his decision to enlist (it can still be read by searching OpinionJournal.com). He had written it weeks before, but wanted it held until he completed the program. In the end, he graduated near the top of his class.

After a well-deserved vacation, Matt Pottinger is going to return to infantry officer training and then perhaps off to Iraq, despite his unusual fluency in Chinese – there are no guarantees. The Marines go where they are needed.

True to form, Matt is a little embarrassed about all the attention – the way he sees it, his story is a common one, replicated every day. But such an open-eyed, long-term commitment is courageous and uncommon. Many of us imagine joining the military, but the personal and professional costs seem too great. Those are easy excuses that Matt Pottinger refused to make.

Appreciation is a standard feature of friendship; but admiration makes fewer appearances. And those of us who are blown away by Matt’s mid-career decision are even more moved by a feeling of pride. Because Matt Pottinger’s decision to move from the comparative comfort of journalism to the front lines in our struggle for civilization is also about the rekindled determination of a generation. It’s about honoring those who have the courage to act on their convictions and in the process inspire the rest of us to stand up and fight for what we believe in.