But, increasingly, he felt that he was merely reacting to crime instead of preventing it.
The U.N. peacekeeping mission in the town abetted the killings instead of preventing them.
Instead of preventing the guru's protest, or letting it take its course, the government tried to control it.
"Instead of preventing, investigating, fighting crime," the judicial police have become "cruel and dangerous criminals," more so "because of the impunity that follows their actions," he said two years ago.
Instead of preventing meritocracy, as some people fear, I believe that quotas help promote it by gradually widening the choice of candidates.
Yet in late 2013, Twitter briefly changed the "block" function so that, instead of preventing abusive users from interacting with you, it simply spared you from seeing their tweets.
Instead of preventing contamination from one sovereign debt to the other and taking the massive measures required by the scope of the crisis, they keep muddling through.
But Caroline Smith DeWaal of the Center for Science in the Public Interest, a supporter of a single agency, said the trouble with much of the legislation is that "it is about responding after the fact to a public health emergency instead of preventing it".
"We learned that, instead of preventing people from using the service on the phone, if we can convince them to come in and use it, they are more likely to upgrade," he said.
Recent studies suggest that it may be possible to develop a vaccine that instead of preventing infection, will control it, prevent the progression of disease and reduce a person's risk of transmitting H.I.V., by holding down the levels of virus in the bloodstream and secretions.
