The importance of this concession to the commercial and political interests of the United States can not easily be overrated. The route by the Isthmus of Panama is the shortest between the two oceans, and from the information herewith communicated it would seem to be the most practicable for a railroad or canal.

The vast advantages to our commerce which would result from such a communication, not only with the west coast of America, but with Asia and the islands of the Pacific, are too obvious to require any detail. Such a passage would relieve us from a long and dangerous navigation of more than 9,000 miles around Cape Horn and render our communication with our possessions on the northwest coast of America comparatively easy and speedy.

The communication across the Isthmus has attracted the attention of the Government of the United States ever since the independence of the South American Republics. On the 3d of March, 1835, a resolution passed the Senate in the following words:

Resolved, That the President of the United States be respectfully requested to consider the expediency of opening negotiations with the governments of other nations, and particularly with the Governments of Central America and New Granada, for the purpose of effectually protecting, by suitable treaty stipulations with them, such individuals or companies as may undertake to open a communication between the Atlantic and Pacific oceans by the construction of a ship canal across the isthmus which connects North and South America, and of securing forever by such stipulations the free and equal right of navigating such canal to all nations on the payment of such reasonable tolls as may be established to compensate the capitalists who may engage in such undertaking and complete the work.

No person can be more deeply sensible than myself of the danger of entangling alliances with any foreign nation. That we should avoid such alliances has become a maxim of our policy consecrated by the most venerated names which adorn our history and sanctioned by the unanimous voice of the American people. Our own experience has taught us the wisdom of this maxim in the only instance, that of the guaranty to France of her American possessions, in which we have ever entered into such an alliance. If, therefore, the very peculiar circumstances of the present case do not greatly impair, if not altogether destroy, the force of this objection, then we ought not to enter into the stipulation, whatever may be its advantages. The general considerations which have induced me to transmit the treaty to the Senate for their advice may be summed up in the following particulars:

1. The treaty does not propose to guarantee a territory to a foreign nation in which the United States will have no common interest with that nation. On the contrary, we are more deeply and directly interested in the subject of this guaranty than New Granada herself or any other country.

2. The guaranty does not extend to the territories of New Granada generally, but is confined to the single Province of the Isthmus of Panama, where we shall acquire by the treaty a common and coextensive right of passage with herself.

3. It will constitute no alliance for any political object, but for a purely commercial purpose, in which all the navigating nations of the world have a common interest.

4. In entering into the mutual guaranties proposed by the thirty-fifth article of the treaty neither the Government of New Granada nor that of the United States has any narrow or exclusive views. The ultimate object, as presented by the Senate of the United States in their resolution to which I have already referred, is to secure to all nations the free and equal right of passage over the Isthmus. If the United States, as the chief of the American nations, should first become a party to this guaranty, it can not be doubted—indeed, it is confidently expected by the Government of New Granada—that similar guaranties will be given to that Republic by Great Britain and France. Should the proposition thus tendered be rejected we may deprive the United States of the just influence which its acceptance might secure to them and confer the glory and benefits of being the first among the nations in concluding such an arrangement upon the Government either of Great Britain or France. That either of these Governments would embrace the offer can not be doubted, because there does not appear to be any other effectual means of securing to all nations the advantages of this important passage but the guaranty of great commercial powers that the Isthmus shall be neutral territory. The interests of the world at stake are so important that the security of this passage between the two oceans can not be suffered to depend upon the wars and revolutions which may arise among different nations.

Besides, such a guaranty is almost indispensable to the construction of a railroad or canal across the territory. Neither sovereign states nor individuals would expend their capital in the construction of these expensive works without some such security for their investments.