That is not enough though, because there are some species that don't seem to a problem right away but then become a problem later. We can work harder to determine the vectors of unintentional introductions, and exercise more control over intentional introductions. We need research that leads to action - not either one in isolation. Some states have noxious weed laws and can list species independently of federal law, but some do not. The interstate control question is a real morass - very little has existed until very recently.
Laws are very different from state to state and conflicting jurisdictions are problematic.