With this in mind, I oppose legalization of prostitution, partly on moral grounds, but mostly for pragmatic reasons. I very much support reducing criminal penalties for prostitution, though.
Is it really fair to compare the prostitution industry of eastern Asia to the United States? They aren't quite the same.
The US and East Asia are different in many ways, but legalized prostitution, whether in Europe, Asia or Nevada, only cleans up the middle and high-end of the industry. The low-end of the industry, where the human trafficking, drugs, etc. is prevalent, relies on large numbers of prostitutes imported from other countries, mostly Central America and Asia in the case of the US. It is even more difficult for a country like the US to solve these problems through legalization, because you will always have wicked criminals who lure young women into the country through lies and intimidation. The same could be said about poor American women and street prostitution.
Legalization will only legitimize people like Charlie Sheen and Eliot Spitzer while leaving untouched the most vile criminal activity associated with prostitution. In every country where it exists, legal prostitution ends up just being way for society to feel good about itself for its purported pragmatism.