A strong woman has been killed by a weak man and the world is a poorer place for it.

Marie Colvin’s death in the besieged Syrian city of Homs was shocking and violent.

Her journalist colleagues have painted a surprising picture of what drove a middle-aged woman to crawl through ditches, drive into pitched darkness with unknown armed men, and join civilians cowering under merciless shellfire in concrete basements.

In a word: anger.

Marie Colvin seems to have had an inbuilt anger: anger at injustice, anger at the wrong meted out to ordinary people in conflicts across the globe, anger at the sheer unfairness of the powerful punishing the poor. She wanted to tell their stories.

Her last report for the Sunday Times is awash with the stories of ordinary people, mostly told in their own words. Yes there’s a small section dealing with her dramatic journey to the city, a wistful paragraph on how beautiful the area would have been in different circumstances, but the piece is essentially not about her (a point missed by many other “celebrity” correspondents). No, the story for Marie Colvin was about the people she found in Homs, the people whose lives and deaths she wanted the world to know about, because what was (and is) happening to them was (and is) wrong.

As a society, we’re broadly uncomfortable with the concept of anger. We usually reserve our own anger for family members, drivers who cut us up, and anyone else guilty of petty or perceived wrongs.

Far more rare, but far more precious, is what Marie Colvin had. A driving sense of righteous anger, a courageous rage against injustice, fury at exploitation of the weak. Maybe Marie Colvin was quite capable of the first type of anger too, but she certainly had the second. She made choices to put herself in harm’s way so that the voices of the poor could be heard.

Righteous anger comes at a price. The desire to tell the story of the oppressed cost Marie Colvin first the sight in one eye, and then her life. We feel compassion for her death because we know something of her, had some basis for empathy and feeling we “knew” her, even though most of us didn’t. She, on the other hand, seemed able to experience these feelings for people she’d never met, but whose suffering she abhorred.

Contrast that with the man whose own choices led to her death. Bashar al-Assad chose as a young man to come to London to study to be an eye doctor. He chose to marry a British woman, Asma from Acton. He appeared to choose a life of doing good, of healing. In different circumstances he would probably be living out that life in London now, and no doubt would have made a caring, compassionate doctor. He would have appeared to be a good man. But how many of the people we see as good – including ourselves – have ever really been put to the test?

Circumstances changed for Bashar al-Assad. The death of his brother Basil in a car crash in 1994 ended his hopes of a life doing good in London: Bashar became the new presumed heir to his father’s power. Perhaps a stronger man would have refused to go back to Syria in the first place. Certainly a stronger man would have found a solution to the current uprising other than murder.

His weakness has cost thousands of lives and the toll is mounting daily. As the conflict started, I found myself willing him (and his British wife) on, to rediscover the values they must have thought they believed in when they lived in London.

But no, it was weakness that won out. Assad and his regime resorted to military might – and nothing demonstrates greater weakness than using the military against your own people. The Syrian opposition movement is, I am aware, an unstable cocktail of religious, political and ethnic groups, with even al-Qaeda trying to muscle in, but that in no way justifies what the UN believes are “highly likely” to be crimes against humanity.

And while weakness may seem easier in the moment, strength is what brings change. Whole empires can be brought down by the strength of one man. Mikhail Gorbachev may not have intended to end the Soviet empire when he became convinced of the case for “perestroika” – change. But that was the end result. A brutal empire built up over decades crumbled and fell because a strong man accepted the need for change.

Bashar al-Assad has demonstrated nothing but his weakness in attempting to use strength to end the uprising in Syria. Yes he’s accepted limited reforms, and yes he’s surrounded by generals and politicians telling him he has no choice but to act tough. Some see him in effect as a puppet, who couldn’t change things even if he wanted to. There’s probably some truth in this. But a strong man would be prepared to be ousted, exiled, even killed, rather than presiding over the massacre of his people.

So a weak man has killed a strong woman – a woman he could easily have known and befriended in London if the Sliding Doors moment in 1994 hadn’t taken his life in another direction.

Thanks to the courage and sacrifice of one woman, the world is more aware than ever of the brutality and cowardice of what’s happening in Syria. The life of Marie Colvin was of no higher intrinsic value than that of the French photographer Remi Ochlik who died with her, or the dozens of other people killed in Homs on the same day, or the estimated 7,000 unnamed Syrians already killed since the uprising began in March 2011.

But let’s hope the shocking loss of such a prominent figure may prove some kind of turning point, and that in death Marie Colvin achieves what she sought so courageously to achieve in life.