Any act or transaction for which protection is claimed under sec. 92 must be a part of trade, commerce or intercourse among the States, that is to say, it must be something done as preparatory to, or in the course of, or as a result of, inter-State movement of persons and things or inter-State communication. There can be no doubt that the use of motor vehicles for the carriage of goods from one State to another for the purpose of sale fulfils this requirement. But it does not follow from the possession of this character that the act of transportation is entirely free from Government control. The question whether sec. 92 applies to a given case involves one or more of several considerations which are susceptible of separate examination. First, the nature and operation of the interference or of the exertion of power complained of, must be considered in order to determine whether it amounts to a restriction of or burden upon the acts or transactions for which immunity is claimed as part of inter-State trade, commerce and intercourse. Second, the nature of the acts or transactions found to be restricted or burdened must be examined in order to ascertain whether they are part of inter-State trade, commerce, or intercourse. Third, the nature and incidence of the restriction or burden must be examined in order to determine whether it belongs to that class freedom from which is secured by sec. 92. For acts or transactions which in fact occur in the course of inter-State trade may be restrained or burdened in consequence of the intervention by the State in the affairs of the citizen for causes which have no relation or relevance to trade, commerce and intercourse among the States. The expression "trade, commerce, and intercourse among the States" describes a section of social activity by reference to special characteristics. The freedom it gives plainly relates to those characteristics. It is only where they are present that the activity is to be absolutely free. It appears to me to be natural to understand a freedom that is so given as referring to restrictions or burdens imposed in virtue of those characteristics upon the presence of which the grant of immunity is based. It is, perhaps, upon some such reasoning that the interpretation of sec. 92 proceeds which confines it to discriminatory laws, that is to forbidding discrimination against inter-State transactions in favour of domestic trade. But that interpretation overlooks the fact that a restriction conditioned on any one of the characteristics which are connoted by the description "trade commerce and intercourse among the States" discriminates against such transactions in favour of transactions from which that characteristic is absent. There is no reason why the freedom should be limited to restrictions based upon the inter-State character of the activity so described. Its character of trade or intercourse is just as essential to the description. "Free" must at least mean free of a restriction or burden placed upon an act because it is commerce, or trade, or intercourse, or because it involves movement into or out of the State. By this I mean that the application of the restriction or burden to the act cannot be made the consequence of that act's being of a commercial or trading character, or of its involving intercourse between two places, or of its involving movement of persons or things into or out of the State.