> Yup, the Constitution does not have a good mechanism for dealing with states racing-to-the-bottom, either in taxes or regulatory climate. This isn't really the kind of thing that you can regulate Federally, either, under the Constitution.

Sure you can; race-to-the-bottom among states only occurs because of the substantial nexus with real interstate and foreign commerce (not a distant potential impact), so even narrow views of the interstate commerce power would give Congress the authority to regulate to control it.