A Louisiana statute requires all bus drivers to obtain a Louisiana bus operator’s license before driving a bus in Louisiana. Anyone can obtain such a license by paying a nominal fee and passing a written test and a road test. The written test is difficult and even experienced truckers must study to pass it. All other states allow anyone with a valid bus operator’s license issued by any state to drive a bus on their roads. Louisiana roads and traffic laws are very similar to those of its neighboring states. A nationwide bus company has challenged the Louisiana law. Which argument against the law is the strongest?