"Our interests are at bottom common; in the long run we go up or go down together. Yet more and more it is evident that the state, and if necessary the nation, has got to possess the right of supervision and control as regards the great corporations which are its creatures; particularly as regards the great business combinations which derive a portion of their importance from the existence of some monopolistic tendency. The right should be exercised with caution and self restraint; but it should exist, so that it may be invoked if the need arises."