On the 18th of June, 1846, A. W. Doniphan was elected colonel of the regiment that he commanded in the Mexican War. In his speech at Independence, Jackson County, Mo., on July 29, 1837, he declared he had not been a candidate for office for seven years, and did not expect to be for the next seventy years to come. The passage by the American Congress of the resolutions of annexation, by which the republic of Texas was incorporated into the Union as one of the States, having merged her sovereignty into that of our own Government, was the prime cause which led to the war with Mexico. However, the more immediate cause of the war may be traced to the occupation by the American army of the strip of disputed territory lying between the Nueces and the Rio Grande.

Bigoted and insulting, Mexico was always prompt to manifest her hostility toward this Government, and sought the earliest plausible pretext for declaring war against the United States. This declaration of war by the Mexican government, which bore date in April, 1846, was quickly and spiritedly followed by a manifesto from our Congress at Washington, announcing that a state of war existed between Mexico and the United States. Soon after this counter declaration, the Mexicans crossed the Rio Grande in strong force, headed by the famous generals, Arista and Ampudia. This force, as is well known, was defeated at Palo Alto on the 18th, and at Resaca de la Palma on May 9, 1846, by the troops under command of Major-General Taylor, and repulsed with great slaughter. The whole Union was in a state of intense excitement. General Taylor's recent and glorious victories were the constant theme of universal admiration. The war had actually begun; and that, too, in a manner which demanded immediate action. The United States Congress passed an act about the middle of May, 1846, authorizing President Polk to call into the field 50,000 volunteers designed to operate against Mexico at three distinct points, namely: The southern wing, or the "Army of Occupation," commanded by Major-General Taylor, to penetrate directly into the heart of the country; the column under Brigadier-General Wool, or the "Army of the Center," to operate against the city of Chihuahua; and the expedition under the command of Colonel (afterward Brigadier-General) Kearney, known as the "Army of the West," to direct its march upon the city of Santa FÉ. This was the original plan of operations against Mexico, but subsequently the plan was changed. Major-General Scott, with a well-appointed army, was sent to Vera Cruz, General Wool effected a junction with General Taylor at Saltillo, and General Kearney divided his force into three separate commands; the first he led in person to the distant shores of the Pacific. A detachment of nearly eleven hundred Missouri volunteers, under command of Col. A. W. Doniphan, was ordered to make a descent upon the State of Chihuahua, expecting to join General Wool's division at the capital, while the greater part was left as a garrison at Santa FÉ, under command of Col. Sterling Price. The greatest eagerness was manifested by the citizens of the United States to engage in the war, to redress our wrongs, to repel an insulting foe, and to vindicate our national honor and the honor of our oft-insulted flag.

The call of the President was promptly responded to, but of the 50,000 volunteers at first authorized to be raised, the service of about 17,000 only were required. The cruel and inhuman butchery of Colonel Fannin and his men, all Americans, the subsequent and indiscriminate murder of all Texans who unfortunately fell into Mexican hands; the repeated acts of cruelty and injustice perpetrated upon the persons and property of American citizens residing in the northern Mexican provinces; the imprisonment of American merchants without the semblance of a trial by jury, and the forcible seizure and confiscation of their goods; the robbing of American travelers and tourists in the Mexican country of their passports and other means of safety, whereby they were in certain instances deprived of their liberty for a time; the forcible detention of American citizens, sometimes in prison and other times in free custody; the recent blockade of the Mexican ports against the United States trade; the repeated insults offered our national flag; the contemptuous ill treatment of our ministers, some of whom were spurned with their credentials; the supercilious and menacing air uniformly manifested toward the Government, which with characteristic forbearance and courtesy had endeavored to maintain a friendly understanding; Mexico's hasty and unprovoked declaration of war against the United States; the army's unceremonious passage of the Rio Grande in strong force and with hostile intentions; her refusal to pay indemnities, and a complication of lesser evils, all of which had been perpetrated by the Mexican authorities, or by unauthorized Mexican citizens, in a manner which clearly evinced the determination on the part of Mexico to terminate the amicable relations hitherto existing between the two countries, were the causes which justified the war.

On the 18th day of August, 1846, after a tiresome march of nearly 900 miles in less than fifty days, General Kearney with his whole command entered Santa FÉ, the capital of the province of New Mexico, and took peaceable possession of the country, without the loss of a single man or shedding a drop of blood, in the name of the United States, and planted the American flag in the public square, where the stars and stripes and eagle streamed above the Palacio Grande, or stately residence of ex-Governor Armigo.

On the 29th of July, 1847, Captain Ruff was dispatched by General Smith with a squadron composed of one company of the Second Dragoons under Lieutenant Hawes and his own company of mounted riflemen, in all eighty-six men, to attack the town of San Juan de los Llanos. In this engagement the Mexicans lost forty-three killed and fifty wounded. Only one American was wounded and none killed. At the battle of San Pascual, on the morning of the 6th of December, General Kearney commanding, with Captains Johnson, Moore, and Hammond as principal aids, drove the enemy from the field. Loss not known. American loss, seventeen killed and fourteen wounded. On the 5th of November, 1846, a small detachment of forty-five volunteers, commanded by Captains Thompson and Burrows, met and totally defeated 200 Californians on the plains of Salinas, near Monterey. American loss, four killed and two wounded. On the 8th of January General Kearney and Commodore Stockton, with 500 men, met the insurgents, 600 strong, to dispute the passage of the river San Gabriel. This action lasted one hour and a half. The next day the Mexicans were again repulsed. Their loss on both days estimated in killed and wounded not less than eighty-five; American, two killed and fifteen wounded. A battle commanded by Doniphan was fought on Christmas day at Brazito, twenty-five miles from El Paso. Mexican loss was seventy-one killed, five prisoners, and 150 wounded, among them their commanding general, Ponce de Leon. The Americans had none killed and eight wounded. On the 27th the city of El Paso was taken possession of without further opposition. On the 13th a battle with the Indians occurred. Americans lost none; Indians had seventeen killed and not less than twenty-five wounded. On the 19th of January, Governor Bent was murdered with his retinue. On the 24th Colonel Rice encountered the enemy. Our loss was two killed and seven wounded. The Mexicans acknowledged a loss of thirty-six killed and forty-five prisoners. On the 3d of February, met the enemy at Pueblo de Taos. The total loss of the Mexicans at the three engagements was 282 killed—wounded unknown. Our total was fifteen killed and forty-seven wounded. On the 24th, in an engagement at Las Vegas, the enemy had twenty-five killed, three wounded; our loss, one killed, three wounded. At Red River CaÑon we were vigorously attacked by a large body of Mexicans and Indians; Americans lost one killed and several wounded; Mexicans and Indians, seventeen killed, wounded not known. At Las Vegas Major Edmondson charged the town; there were ten Mexicans slain and fifty prisoners taken. On the 9th of July a detachment of Captain Morin's company was attacked; five of our men killed and nine wounded. On the 26th of June Lieutenant Love was attacked and surrounded by Indians; they cut their way through with a loss of eleven; the Indians lost twenty-five. On the 27th of October Captain Mann's train was attacked; American loss, one killed, four wounded; Indian loss not known.