A large part of the commerce of the United States today does concern more than a single state. The great railroads traverse several states, sometimes a dozen or more of them. Goods sent from New York to Los Angeles pass through ten or twelve states on their journey. Even street car lines sometimes cross the state boundaries. To the trader a state boundary means nothing; it is only a mark on the map. Trade moves wherever the chance of profit appears. It pays no attention to political divisions within the country. [Sidenote: What interstate commerce includes.] Interstate commerce, then, includes all agencies of trade among the states: steamships, sailing vessels, railroads, street railways, motor trucks, telegraphs, telephone systems, oil pipelines, power lines, and all passengers, goods, messages, or anything else carried by them. All persons who have to do with such things are engaged in interstate commerce. But interstate commerce does not include the manufacture of goods in any state, even though they be intended for sale in other states. Commerce does not begin until the product is finished and started on its way. Once started on their way, with a destination in another state, the goods pass under the supervision of the national government. Passengers traveling from Chicago to St. Louis, or goods shipped from one of these cities to the other, or messages exchanged between them by telegraph, for example, are under the supervision of the national government from start to finish. Illinois and Missouri have nothing to do with them. [Sidenote: Railroads and steamships were at first not regulated.] =How Interstate Commerce is Regulated.=—For many years after the constitution was adopted there was no need for the regulation of interstate commerce because so little of it was carried on. Not until the era of steamships and railroads did commerce develop to a point where any strict regulation was necessary. The earliest railroads, moreover, were short lines constructed and operated wholly within single states. They were built by corporations under charters granted by the states. Frequently these charters were given for an indefinite term, and they placed no limits upon the rates which the railroad might charge for the transportation of passengers and goods. The chief concern of the people in those days was to get railroads built. As time went on, however, the state authorities became more strict in granting charters for the construction of railroads and, finally, most of them established commissions to protect passengers and shippers from unreasonable rates.