The Supreme Court would invalidate it

The anti-discrimination prong is most relevant to state and local exit taxes. Exit taxes implicate the anti-discrimination prong because they apply only to taxpayers engaged in interstate activities—i.e., individuals moving from one state to another—and not to taxpayers engaged solely in intrastate activities. If a state tax law has a discriminatory impact on interstate commerce, the United States Supreme Court will generally invalidate the law without balancing the competing state interests.139