Global criminal justice to support migration

Assuming you aren't a person who embraces migration control as a way to protect jobs and bolster the economy, then the only real problem with open-borders is that they allow trafficking of drugs, prostitutes, and other enslaved/exploited people into lucrative markets where they can be exchanged and/or used to make big money.

So if national governments could cooperate to stop transnational crime, would it then be possible to allow non-criminal migrants to freely go where they want and participate in the local economies wherever they live?

Or do you defend the right of national populations to reject migrants simply on the basis of ethno-cultural prejudices, economic protectionism, or other (collectively) selfish reasons?