Immediately after Congress had recognized the existence of the war with Mexico my attention was directed to the danger that privateers might be fitted out in the ports of Cuba and Porto Rico to prey upon the commerce of the United States, and I invited the special attention of the Spanish Government to the fourteenth article of our treaty with that power of the 27th of October, 1795, under which the citizens and subjects of either nation who shall take commissions or letters of marque to act as privateers against the other “shall be punished as pirates.”

It affords me pleasure to inform you that I have received assurances from the Spanish Government that this article of the treaty shall be faithfully observed on its part.  Orders for this purpose were immediately transmitted from that Government to the authorities of Cuba and Porto Rico to exert their utmost vigilance in preventing any attempts to fit out privateers in those islands against the United States.  From the good faith of Spain I am fully satisfied that this treaty will be executed in its spirit as well as its letter, whilst the United States will on their part faithfully perform all the obligations which it imposes on them.

Information has been recently received at the Department of State that the Mexican Government has sent to Havana blank commissions to privateers and blank certificates of naturalization signed by General Salas, the present head of the Mexican Government.  There is also reason to apprehend that similar documents have been transmitted to other parts of the world.  Copies of these papers, in translation, are herewith transmitted.

As the preliminaries required by the practice of civilized nations for commissioning privateers and regulating their conduct appear not to have been observed, and as these commissions are in blank, to be filled up with the names of citizens and subjects of all nations who may be willing to purchase them, the whole proceeding can only be construed as an invitation to all the freebooters upon earth who are willing to pay for the privilege to cruise against American commerce.  It will be for our courts of justice to decide whether under such circumstances these Mexican letters of marque and reprisal shall protect those who accept them, and commit robberies upon the high seas under their authority, from the pains and penalties of piracy.

If the certificates of naturalization thus granted be intended by Mexico to shield Spanish subjects from the guilt and punishment of pirates under our treaty with Spain, they will certainly prove unavailing.  Such a subterfuge would be but a weak device to defeat the provisions of a solemn treaty.

I recommend that Congress should immediately provide by law for the trial and punishment as pirates of Spanish subjects who, escaping the vigilance of their Government, shall be found guilty of privateering against the United States.  I do not apprehend serious danger from these privateers.  Our Navy will be constantly on the alert to protect our commerce.  Besides, in case prizes should be made of American vessels, the utmost vigilance will be exerted by our blockading squadron to prevent the captors from taking them into Mexican ports, and it is not apprehended that any nation will violate its neutrality by suffering such prizes to be condemned and sold within its jurisdiction.