Manifest Destiny and the Mexican War : SO FAR FROM GOD The U.S. War With Mexico 1846-1848<i> by John S.D. Eisenhower (Random House: $24.95; 436 pp., illustrated; 0-394-56051-5) </i>

Until the Louisiana Purchase, the country west of the Mississippi River was largely a blank space on the maps of the United States. But after the Lewis and Clark expedition to the shoreline of the Pacific, reports, stories and rumors of this new frontier captured the imagination of pioneers and politicians. By the 1840s, the westward movement began a steady intrusion into these vast spaces that Mexico considered its own by right of first discovery, and the establishment of missions, military outposts, and settlements.

In what Bernard De Voto called “The Year of Decision,” the United States and Mexico began a bloody war that lasted from 1846 to 1848. As the United States saw it, the war grew out of Mexico’s threatening behavior after the United States declared Texas a state, ignoring Mexico’s claim to the land.

Newly elected President James Knox Polk had spurned Mexico’s claim, sending Gen. Zachary Taylor and a force of 2,000 soldiers from Ft. Jesup in Louisiana across the Sabine River with orders to move toward the border. While this force constituted “about one-quarter of the fighting power of the U.S. Army in 1845,” as John S. D. Eisenhower states, it certainly showed that President Polk must have had the idea of following this initial strike with a full army of conquest, one which would have more duties than observation.

So the struggle for much of the Far West began, and Eisenhower’s re-examination of this little known war of conquest makes “So Far From God” a fine introduction to the background of a major event that illuminates our historical relationship with Mexico. This far-ranging military history also shows the first experiences under fire of men such as Ulysses S. Grant and Robert E. Lee, who were to be key officers on opposite sides during the Civil War.

Eisenhower brings his background as a former Army general to bear upon the wide range of battles in this war. He points out the struggles between officers in command positions in both the American and Mexican armies; elaborates the strategies in such battles as Buena Vista, where Taylor’s forces fought and defeated a much larger army commanded by Gen. Antonio Lopez de Santa Ana; points out the amphibious landing--a first--of Gen. Winfield Scott’s forces at Vera Cruz; and covers the war in the West that saw Gen. Stephen Watts Kearny capture Santa Fe, N.M., without firing a shot.

Another phase of this far-flung war saw Col. Alexander W. Doniphan cross the Rio Grande and march toward Chihuahua City with his Missouri Volunteers, frontiersmen and Santa Fe traders, whose wagons were loaded with trade goods. This wild and strange-looking army came up against a much larger Mexican army at Rancho Sacramento not too many miles north of Chihuahua City. However, as Eisenhower points out, the Mexican army with its bright uniforms and inferior artillery was dug in on a rise in a fixed position. The unorthodox Americans swung to the side of the Mexican artillery, followed the trade wagons and used them as moving forts and poured volley after volley of deadly fire into the Mexican forces. The surrender came very quickly, and the Americans lost only one man. Then they stopped to aid their wounded foe. When this was done, the army and the wagons quickly headed for Chihuahua City where the Santa Fe traders wasted no time as they got ready to trade with the local citizens.

The other phase of the Mexican War in the West took place in California where John C. Fremont’s Third Exploring Expedition had already backed into a stand-off with Gen. Jose Castro near San Juan Bautista. But as Fremont set up camp at the Sutter Buttes, near present-day Marysville, the ragtag Bear Flag army of Americans living in California captured Sonoma early in the morning of June 14, 1846, when this rough band knocked on Gen. Mariano Vallejo’s door and were invited into La Casa Grande where Vallejo served them wine and brandy from his cellars as the Osos told him he was under arrest. Then as the Bear Flaggers got drunk at Vallejo’s gracious table, sober William Ide took over for the Americans and they began the work on a constitution for the Bear Flag Republic.

The backing of Capt. Fremont in the taking of Sonoma, however, was not an immediate event as Eisenhower describes it, for it did not begin until Fremont and his men reached Sonoma on June 25, 1846; and he didn’t form the California Battalion until July 5, 1846.

The rest of the taking of California moved rapidly as Fremont captured San Jose and San Juan Bautista on his way to Monterey, where his men boarded Capt. Robert Stockton’s ship for their voyage of conquest to Southern California. This went easily at first, but when Fremont returned to the north, the Californios retook Los Angeles and San Diego for a time; then headed southeast as they retreated from Stockton’s men. But in the open country at San Pascual, they punished the tired troops of Gen. Stephen Watts Kearny. Their victory was short-lived, as they surrendered to Fremont at Cahuenga Pass on Jan. 13, 1847.

“So Far From God” highlights a tough war that cost 13,780 American lives, and many more dead and wounded Mexican soldiers. When it was all over, the principal result, as Eisenhower shows, was a forgotten American war of conquest under the guise of Manifest Destiny. The end result for Polk’s unpopular war was the acquisition of California, New Mexico, Arizona, Utah, Nevada, and parts of Colorado and Wyoming. In addition, the United States inflicted a wound on Mexico and Latin America that has yet to completely heal. For those who want to grasp the military and political causes of this invasion of our neighbor south of the border, Eisenhower’s history is an excellent source.