St. Lawrence into the Lakes with facility. We cannot do it at all. Great Britain has constructed canals for this express purpose. We have no such military canals.”30
The concern about Great Britain and a possible naval attack did not lessen after the end of the Civil War. In 1867 the United States Congress commissioned a report on enlarging the I. and M. Canal, amongst other studies aimed at making the waterways above St. Louis larger so river boats could travel to the Great Lakes. The officer-in-charge of these surveys was Brevet Major General J. H. Wilson. In his report on the survey, he lays a heavy emphasis on the defense needs. His report to the Secretary of War and Congress is to our eyes startling, but it expounds on what could be called a hydraulic concept of defense.
“A thorough discussion of these improvements [of the Illinois River] in their military, commercial, and political aspects, if necessary, would be out of place at this time, but I cannot forgo a passing allusion to them. The recent confederation of the British American provinces shows the anxiety felt by the English government in this behalf, and must be regarded as a movement in hostility to the people and institutions of the United States.
“While it does not actually increase the aggregate British strength on our Northern Frontier, nor in any way encroach upon our territorial rights, it consolidates the policy in regard of canals, as well as other matters, and renders available the entire force of those provinces in any difficulty that may arise between England and the United States. The English are already able, by means of a system of internal canals, to pass gun boats of nine feet draft into Lake Erie and Ontario, and are contemplating a new canal which will enable them to reach Huron without coming in reach of American territory at any point. The canals already finished were constructed avowedly for military as well as commercial purposes, and in case of war will enable the English to drive our commerce from the lakes and destroy or lay under construction nearly every important city on our Northern Frontier. But in addition they can inflict upon us a still more vital injury when they have gotten possession of the Lakes by severing the main line of our communication with the east for heavy products. [emphasis in the original]
“...We are debarred by treaty stipulation from keeping a navy upon the Lakes, as this may be well enough [for it saves the cost of building ships]....But as we have no communication between the Lakes and the sea coast suitable for vessels of war, we cannot expect to meet the enemy upon anything like terms of equality when the emergency arises. It will not do to depend upon permanent defenses for the purposes of barring the entrance to the Lakes, for unfortunately they cannot be so situated, nor so constructed, as to completely subserve the object in view.
“There are but two ways in which we can thoroughly protect our Northern Frontier in time of war, and relieve ourselves of a continuous menace in times of peace. The government must either connect the lakes and the Mississippi river by a canal of sufficient capacity to accommodate gun boats suitable for service on the lakes, or prepare for the annexation or conquest of Canada. [emphasis in the original] As a military measure the construction of a canal will be effective, and fortunately for this country this can be done at an expense which must be regarded as insignificant when compared with the objects to be obtained.”31