I would propose the question is not, do we want to legalise the trade of people? -which obviously we don't, but, do we want to lessen, and ultimately eradicate, the conditions that pressure people to enter into the types of relationships where they find themselves being bought and sold?

In sex trafficking and labor trafficking the trafficker is most often taking advantage of the vulnerability of someone who can not migrate using legal means.

A smuggling, or trafficking network, offers someone a service and opportunity they could not get in their country of origin -perceived access to greater opportunity through entrance into a foreign country that they can not access "legally". Once they have entered into a relationship with these networks they can then become ensnared in a brutally exploitative situation.

People use smuggling networks or end up in trafficking networks to access opportunities they cannot get through legitimate means of migration. The majority of people in this world cannot migrate through means legitimated by destination countries.

Thus to parallel kcurie's drug legalization model, if destination countries offered people with legal means to move to and from more freely, the need for the services offered by smuggling networks would be greatly reduced, if not made useless all together. The corresponding opportunity for exploitation and abuse by these networks, which we refer to as trafficking, would equally reduce.

On the country of origin side, one thing that can contribute to the "push" factors are economic policies from developed countries that are weighted in favor of the developed country. To ask a country made up of small and mid-size farmers to open their market to cheap agricultural products grown on highly subsidized industrial scale farms can remove the economic means of survival from an entire class of people. (I should add, highly subsidized industrial scale farms that often used exploited, and sometimes trafficked, migrant labor).

Once this class of people have lost their means of making a living, well... they have to go look for work, which most often means the need to migrate.

Developed countries' talking points about globalization often discuss the movement of goods and services but rarely include discussions about the movement of people.

It is ironic that with one hand politicians from developed countries make big bold noble statements against the evils of human trafficking and the "commodification" of people, and then with the other hand push imbalanced trade policies and greater restrictions on the flow of people across their borders.

If interested, here is a link to an audio interview on the potential for the Central American Free Trade Agreement (CAFTA) to contribute to the conditions that could lead to an increase in human trafficking.