As a native Nevadan, I grew up in the only state in the U.S. to have legal prostitution. In Nevada, it is only legal outside of city limits, and only in particular counties. The girls are tested regularly and they are treated as legal workers. However, a great many prostitutes operate illegally inside the cities and are never tested. So, the legality of the practice does not necessarily keep it clean and off the streets. Only the workers in the licensed brothels are tested and regulated. Legalization doesn't reduce the amount of illegal sex trade, it merely increase the overall amount of prostitution that happens.
Let me be clear: I am not against legal prostitution, but I think it is important to keep harm reduction in mind when creating legal policies that govern the sex trade. The main problem we see with legal prostitution in Nevada (and elsewhere) is that there is always a percentage of sex workers who are enslaved. Sexual trafficking is not always easy to identify - often girls who try to flee are beaten and threatened, or even killed. In Germany, where sex trade is legal, authorities estimate that at any given time about 10-14% of prostitutes are working under threat of death or harm. Many are from other countries and are trafficked by mafias and corrupt officials.
In most sex for trade transactions, the seller is at a disadvantage. It is the seller who is desperate - 95% of prostitutes would leave the work if they had a choice.
sfu.ca/cmns/research/newswatch/test_folder/Representat...prostitution.htm
However, there are some sex workers who do enjoy their work and perform it willingly. So, the question becomes how do we allow consenting adults to engage in this practice, but still protect sex workers from abuse and slavery?
The Nordic model is one approach that has been successful in reducing harm and negative side effects from prostitution. Basically, their law attacks the "demand" part of the equation. The selling of sex is decriminalized, but the buying of sex is outlawed. This legal model places the liability squarely on the shoulder of the buyer, the person with the money. The seller is seen as a victim, and is not punished, but empowered to report the buyer if need be. Sweden, Norway, Finland, Iceland and Denmark all have variations of this approach encoded into law. Finland still allows the selling of sex in one-on-one negotiations between consenting adults, who are citizens. But, their regulations strictly outlaw any and all kinds of third party brokering of sex: no pimps, no madams, no brothels. Non-citizens are also barred from sex work in Finland, this byline is intended to specifically thwart the sex trafficking of Asian and Russian women.
I like the Nordic model for harm reduction pretty well, but my own views are somewhat different and can be reviewed in more depth here: daerice.wordpress.com/2013/02/28/sacred-prostitution-a...rchetypal-whore/
Sources on Harm Reduction studies related to prostitution:
Cho, Seo-Young, Dreher, Axel and Neumayer, Eric. "Does Legalized Prostitution Increase Human Trafficking?" World Development, 41 No. 1 (2013): 67-82.
Danailova-Trainor, Gergana, and Patrick Belset. "Globalization and the illicit market for human trafficking: an empirical analysis of supply an demand." Policy Integration Department, International Labour Office Geneva. Working Paper No. 78, December 2006. ilo.org/wcmsp5/groups/public/---dgreports/---integrati.../wcms_081759.pdf. Accessed March 18, 2013.
Skilbrei, May-Len and Charlotta Holmstrom. "Is There a Nordic Prostitution Regime?" Crime and Justice Vol 40, No. 1 (2011): 479-517.) 0-www.jstor.org.innopac.library.unr.edu/stable/10.1086/659841. Accessed March 18, 2013.