For a long time, I believed the death penalty to be a legitimate, albeit severe punishment for severe crimes. In Egypt, where I grew up, there was nothing exceptional about this view; in fact I don't recall hearing anyone expressing a different view until a few years into university.
In much of the Middle East and North Africa, the death penalty was and continues to be widely seen as a legitimate and just punishment for the worst crimes. The same is true in many countries that retain the death penalty as a punishment.
But many years later, my views have completely altered. I did not have a sudden change of heart; it took many years for initial doubts to grow into opposition of the death penalty.
First it was its widespread application. In the 1990s, many people were sentenced to death in military and special courts in Egypt in relation to a wave of terrorist attack. Yes, these were atrocious acts and had to be punished, but were so many people involved? Was everyone found "guilty" really guilty or were the trials unfair?
If you look across the world, there is a great degree of variation in the crimes that can be punished by death. Common ones are crimes resulting in death. But the death penalty is also applied to crimes ranging from adultery, rape, sorcery, drug-related crimes, aggravated robbery, apostasy, blasphemy, economic crimes and treason.
Even for those who believe that the death penalty should be a punishment for heinous crimes, this wide variation in the scope of its application should raise alarm bells.
If people can be executed in the name of justice for acts that should not be considered crimes at all, then surely the societal imperative to punish these acts, let alone impose the death penalty, is mistaken.
How can someone be killed for "adultery" or "apostasy" if these are not even deemed to pose a threat to the public in so many countries?
Look closely and you will find that the death penalty tends to affect specifically disadvantaged groups. Poor people and minorities are at increased risk of being executed. For example, in the USA, there is mounting evidence that African-Americans are more likely to receive a death sentence - and be executed - because of their race.
In Saudi Arabia a large proportion of those executed in the past few years were migrant workers from poor and developing countries; they often have no defense lawyer and are unable to follow court proceedings in Arabic. On 7 October 2011, eight Bangladeshi men were beheaded for an alleged 2007 murder.
It became clear to me that such a harsh punishment was inherently problematic, also because it is disproportionately used against those who are less able to defend themselves and those who suffer from wider discrimination.
There is no escaping that the death penalty is an act of violence. Is more violence the right way to respond to crime?
One of the biggest justifications for the death penalty is that it supposedly acts as a deterrent against committing the most serious crimes. But let's call this argument what it really is: wishful thinking. There is simply no convincing evidence that the death penalty deters from crime more than other forms of punishments.
In fact, there is evidence to the contrary. In the USA, the average murder rate in states that use the death penalty is higher than for those that do not. More than three decades after abolishing the death penalty, Canada's murder rate remains over one third lower than it was in 1976. A 35-year study compared murder rates between Hong Kong, where there is no death penalty, and Singapore, which has a similar size population and at the time executed regularly, finding that capital punishment had little impact on crime rates.
The death penalty - although far from alone in this respect - is an example of how public policy and legal systems fail to take evidence into account.
If, like me, you grew up thinking the death penalty was just, then consider this. In 1997, 21-year old Chiang Kuo-ching was executed for sexually abusing and murdering a five-year-old girl. Almost everyone will agree this is a horrendous crime that deserves the harshest punishment.
In 2011, Chiang was acquitted. It was too late for him and for his family.
Executions are irreversible. They make a mockery of any justice system, which will always be as fallible as we are.