Ample corroboration of the reports then circulated was found in my inquiries regarding the quantity of forage we could depend upon getting in Mexico, our arrangements for its purchase, and my sending a pontoon train to Brownsville, together with which was cited the renewed activity of the troops along the lower Rio Grande. These reports and demonstrations resulted in alarming the Imperialists so much that they withdrew the French and Austrian soldiers from Matamoras, and practically abandoned the whole of northern Mexico as far down as Monterey, with the exception of Matamoras, where General Mejia continued to hang on with a garrison of renegade Mexicans.
The abandonment of so much territory in northern Mexico encouraged General Escobedo and other Liberal leaders to such a degree that they collected a considerable army of their followers at Comargo, Mier, and other points. At the same time that unknown quantity, Cortinas, suspended his free-booting for the nonce, and stoutly harassing Matamoras, succeeded in keeping its Imperial garrison within the fortifications. Thus countenanced and stimulated, and largely supplied with arms and ammunition, which we left at convenient places on our side of the river to fall into their hands, the Liberals, under General Escobedo—a man of much force of character—were enabled in northern Mexico to place the affairs of the Republic on a substantial basis.
But in the midst of what bade fair to cause a final withdrawal of the foreigners, we were again checked by our Government, as a result of representations of the French Minister at Washington. In October, he wrote to Mr. Seward that the United States troops on the Rio Grande were acting “in exact opposition to the repeated assurances Your Excellency has given me concerning the desire of the Cabinet at Washington to preserve the most strict neutrality in the events now taking place in Mexico,” and followed this statement with an emphatic protest against our course. Without any investigation whatever by our State Department, this letter of the French Minister was transmitted to me, accompanied by directions to preserve a strict neutrality; so, of course, we were again debarred from anything like active sympathy.