Mr. Seward to the Marquis de Montholon

Sir: I have the honor to recur to your note of the 19th ultimo, in which complaints are made of violations of the neutrality of the United States on the Rio Grande, and to my note of the 31st of October, acknowledging the receipt thereof.

The first complaint is, that the “dissenting forces of Cortinas are recruiting many colored persons, and that this partisan chief passes the Texan frontiers whenever he pleases, going to Brownsville to procure whatever he needs.” These representations were submitted to the Secretary of War for such information and such opinion as he might think proper to submit to the President.

It appears that upon these points the Secretary of War has no information. Major General Sheridan was instructed to preserve the same neutrality that had been observed towards the United States by the French or imperial party, when Brownsville and the greater portion of the Rio Grande was held by the rebels. If it should be ascertained that the insurgents had been able to cross and recross the Mexican frontier at will, and go into Matamoras with a view of obtaining what they required, then existing instructions might authorize a corresponding course on the part of this government towards the liberals. The Secretary of War is not aware of the existence of any regulation which prevents either imperialist or liberal from crossing the Texas frontier, or proceeding to Brownsville to make purchases; and if recruiting has been allowed by officers in command, it has been without the authority of the Secretary of War. I am of opinion that, American emigration having been invited to Mexico by the imperial party, there is neither law nor order preventing it; and that, as the republican government of Mexico is acknowledged by the United States, there can be properly no objection urged to such of their citizens as may choose going to Mexico, and taking, when there, whichever side they may prefer.

It is admitted that while the United States hold their present attitude towards Mexico, military commanders should not allow either party to recruit soldiers upon United States territory.

With regard to the second complaint, namely, that “about the last of July, 1865, Cortinas attacked the steamer Señorita on the river, loaded with cotton, taken on board that vessel at Camargo, and destined for Matamoras; that the attack occurred on Texas ground, and that the captured vessel was made fast to the Texas shore, where she has remained in possession of the dissenters since the 27th of July last; that in the course of the same month a convoy of goods was to start for Monterey, and that Cortinas, who was in Brownsville, heard of it, and enlisted men openly to attack the convoy; his armed troops crossed the river,” &c., it is conceded that, if the facts were as represented, the conduct of the commander at Brownsville was entirely inexcusable. These complaints have been referred to Major General Sheridan, commanding the military division of the Gulf, with suitable instructions and directions to report the facts as to what had previously occurred.

It is stated by the Secretary of War that the United States have a long frontier upon the Rio Grande, where none of our troops are stationed; that either of the belligerents might easily commit acts of war upon the other from United States soil without such acts being known in time to prevent them.

Accept, sir, a renewed assurance of my very high consideration.

WILLIAM H. SEWARD.

The Marquis de Montholon, &c., &c., &c.