The news of this engagement reached Wash ington early in May, and on the llth President Polk sent a special war message to Congress. After speaking of the failure of the Slidell mis sion and explaining the movements of General Taylor, he went on to say that war already existed, that it existed by the act of Mexico it self and, consequently, that it was the duty of the American people to vindicate the honor, the rights and the interests of their country. (See MEXICAN WAR). The whole question hinged upon the ownership of the Nueces-Rio Grande strip. According to the President this district belonged to the United States, and the war was, therefore, defensive in its origin. On the other hand, if the Mexican claims to the strip were valid, Polk exceeded' his constitutional powers in beginning an offensive war without the con sent of Congress. However, the President's po sition was safe enough because Congress had already recognized the country beyond the Nueces as American territory, by including it within the revenue system, and the Senate had ratified the appointment of a revenue officer. Two days after the message was received an act was passed providing for the vigorous pros ecution of the war.
Whether or not the war was defensive in origin, it was certainly not long conducted on that basis. After his successes at Palo Alto, 8 May, and at Resaca de la Palma, 9 May, Taylor crossed the Rio Grande and captured Matamoras on the 18th, before he could pos sibly have heard of the Congressional act of the 13th. The President's military orders showed
clearly his intention to seize Mexican territory. General Kearney was authorized to occupy New Mexico, Commodore Sloat to take possession of Upper California and Taylor to prosecute the war in Mexico. These orders were faithfully executed. Kearney captured Santa Fe and brought all of New Mexico under subjection. Fremont and Commodore Stockton, who had succeeded Sloat, were equally successful in Cal ifornia. Taylor made his way slowly into the interior. In September, after defeating an army under Ampudia, he captured Monterey.
The anti-slavery Whigs in Congress pointed to these facts as evidence that the war was not being waged to protect the honor of the United States, but purely in order to seize the territory of a weaker power. Among the discontented was Abraham Lincoln, who was elected to Con gress in 1846. Jefferson Davis approved of the war and resigned his seat in Congress to lead a Mississippi regiment. In general the con flict was popular in the South and unpopular in the North, the strongest opposition being in New England. Lowell's keen satires in the (Bigelow Papers> represent well the sentiment of that section of the country. See LOWELL,