In the case of competition between a direct and a longer, more roundabout line, which one "controls" or fixes the rate? It is an important matter, involving as it does the economic, if not the legal, right of a carrier to participate in any given traffic. Concerning this question the greatest diversity of opinion prevails. On the one hand, both writers[239] and practical railway men[240] aver that the short line makes the rate, while the long line merely meets the rate thus made. This is probably the more prevalent opinion. Yet expert evidence of an opposite sort is to be had for the seeking. The Interstate Commerce Commission has repeatedly held that the short line is at the mercy of the longer line under certain circumstances;[241] and traffic managers not infrequently plead their inability to control rate situations in the face of irrepressible, roundabout competition.[242] There is evidently a confusion of thinking, or else a loose use of terms where statements are so conflicting. As a matter of voluntary agreement among roads, or of prescribed rates under government regulation, the issue often assumes the form of controversy as to whether a road operating under a physical disability shall be permitted to participate in a given business by a concession in rates or not. Thus in the notable Milk Rate cases it was a question whether roads with heavy grades should be allowed to make concessions in rates. This issue really also underlies the question of enforcement of the long and short haul clause. In the recent Spokane case the Harriman lines to St. Paul asked that they, being long lines, should not be compelled to reduce their rates to the figure prescribed for the direct Hill roads. It is clear in the first place that "short line" and "long line" are merely used as convenient terms to designate differences in the cost of operation. This was well put by James J. Hill before the Elkins Committee of 1905. "We will say that the distance from Cincinnati to New York is 800 miles, and that they haul 800 tons behind one locomotive on one per cent. ruling grades. Now somebody else builds a road with a 0.3 grade, and he can haul 2,000 tons--twice and a half the amount; but that line is 200 miles longer. You can see readily that to move a given number of tons the second road runs less than half the train miles, so that the farthest way round is the nearest way home in that case."