To fully understand how enforcement provisions work, please read the article on this website – particularly Lactation and the Law.
The short answer to the question is that if a law has no enforcement provision, there is nothing you can do if the law is broken. The vast majority of public breastfeeding laws in the United States have no enforcement provision. That means that while a state may have a law that says a mother has a right to breastfeed in public, if someone harasses her while she does it, there is probably no legal action she can take against the harasser. Depending on the circumstances of a particular incident, there may be a lawsuit a lawyer can bring but, by and large, women can not afford lawyers, few lawyers will take breastfeeding cases pro bono, and there are few viable legal claims. In short, a breastfeeding law without an enforcement provision is of little to no value to breastfeeding women.