Federal law requires most interstate truckers to obtain a permit that reflects compliance with certain federal requirements. The 1965 version of the law authorized states to require proof that a truck oper- ator had such a permit. By 1991, 39 states had demanded such proof, requiring a $10 per truck registration fee and giving each trucker a stamp to affix to a multistate "bingo card" carried in the vehicle. Finding this scheme inefficient and burden- some, Congress created the current Single State Registration System (SSRS), which allows a trucking company to fill out one set of forms in one state, thereby registering in every participating state through which its trucks travel. A subsection of Michigan's Motor Carrier Act imposes on truck companies operating in interstate commerce an annual fee of $100 for each self- propelled motor vehicle operated by or on behalf of the motor carrier. The American Truckers Associa- tion (ATA) and others challenged the $100 fee as preempted by the extensive federal regulation of interstate trucking and trucking companies. The ATA and others appealed to the U.S. Supreme Court. What should the U.S. Supreme Court do? Be sure to discuss what portion of the Constitution applies to this issue. American Trucking Asociations Inc. v. Michigan Public Service Com n. 545 U.S. 429