The most devastating event in the Mexican history was the war with the USA. California, Arizona, New Mexico, Nevada, Colorado and Montana were taken by military force from Mexico. This area is larger than Spain, Italy and France combined. Even Abraham Lincoln, then a young Congressman, and Ulysses S. Grant, the future Civil War victorious commander and US President, believed that the invasion of Mexico was not justified.

“War is like love; it always finds a way.” In the mid-1840´s, both America and Mexico seemed determined to “find a way” to settle their differences, and the courting wasn´t amorous.

Mexico had just rejected a $15 million cash-for-land deal offered by the US. The area included what now covers the states of California, Arizona, New Mexico and parts of Colorado and Utah. This territory was Mexican, but only nominally; control over the area was slight, and open to intrusion.

Irritated at the rebuff, the US struck back in1845 by annexing Texas, a territory long disputed and fought over by both countries. Mexico responded by severing diplomatic relations. US President Polk, a no-nonsense backwoods lawyer from Tennessee, further provoked Mexico by moving troops south to the Rio Grande, a river that historically was considered well within Mexico. US and Mexican troops skirmished across the river, leading Polk to declare to Congress on May 11, 1846, that “…the cup of forebearance (has) been exhausted,” and that “American blood (has) been spilled on American soil.”

The US-Mexican War is the pivotal chapter in the history of North America. It is the war that sealed the fates of it's two participants. For the United States, the War garnered huge amounts of territory and wealth, bootstrapping the fledgling democracy onto the world stage. For Mexico, the War sent the emerging nation into a tailspin that it is still reckoning with today, one hundred fifty years later.

In the United States the US-Mexican War is virtually forgotten, and for good reason, as it is the clearest example of historical hypocrisy. The US-Mexican War was waged upon Mexico out of pure greed and moral righteousness. The remarkable part of the story is that at the time of this unjust invasion of a peaceful Catholic neighbor, Irish immigrants fresh off the coffin-ships from the Famine identified with Mexico's plight.

Over a hundred years before the conscientious objectors of Vietnam, the 'San Patricios' were true heroes who fought and died for their religion, their convictions, their brethren, and their adopted homeland Mexico. While Henry David Thoreau invented civil disobedience in Massachusetts, refusing to pay his taxes to support this unjust invasion of Catholic Mexico, and while Abraham Lincoln stood in opposition to President Polk's scheme in Congress, the 'San Patricios' fought to the death in the front lines against the invading Yankees.

As the war progressed, the Irish grouped in the San Patricio battalion, under a green banner with St Patrick and the Mexican eagle, distinguished themselves as artillery specialists and inflicted heavy casualties on the US invaders at the battles of Monterey and Buena Vista. But the Mexican forces were being pushed back towards the capital as Santa Anna made a series of tactical blunders. The US army now under the command of a tough Virginian, General Winfield Scott (Old Fuss and Feathers), landed at Veracruz and marched on the capital.

The San Patricios, whose bravery and skill were noted by the Mexican officers, fell back with their allies on Mexico City. Those who survived the Churubusco battle and were captured were soon court-martialed for desertion. The historian, Michael Hogan, author of The Irish Soldiers Of Mexico, says the punishments inflicted on the Irish went beyond what was allowed by the military code of the day and that the whole episode was denied for years by the US army and still remains deeply hidden in USA history to this very day.

The hangings and brandings were particularly brutal. Thirty of the condemned were forced to wait for hours with the noose around their necks until the final Mexican surrender at Chapultepec Castle.   This mass hanging, according to Robert R. Miller, author of "Shamrock and Sword," was the largest group execution ever carried out in U.S. military history. Those few who were spared received 50 lashes and had their faces branded with hot irons.

Mexico lost the war because the balance between politics and the military became unhinged and thus destroyed any semblance of strategy. This resulted in a lack of control on the battlefield. Few Mexican commanders had any idea as to what was happening during most battles. Their tactics were poorly conceived and doomed to failure although the bravery of the Mexican soldier was unquestioned. The difference between the two sides was the fact the President of Mexico also conducted field operations; a relic of European command structure unsuited for the innovative strategy employed by the Americans.