You may know that California--as well as Arizona, New Mexico, Colorado, Nevada, Utah, and even Texas--were once part of Mexico. So how did the current border get drawn, and why?

The United States and Mexico went to war over Texas in 1846. (Texas had been in dispute for ten years, but that's another story for another time.) After a year of rather sporadic war, President James Polk sent an envoy to be in place to negotiate a peace treaty. Travel was slow in those days, so Polk was looking ahead.

The man he chose as envoy, Nicholas Trist, spoke Spanish fluently. That was a big plus. He was also married to Thomas Jefferson's granddaughter--in fact, he had been Jefferson's personal secretary during the last years of Jefferson's life. He'd been private secretary to President Andrew Jackson, too. In 1846, he worked for the State Dept, directly under Secretary of State James Buchanan (who later became president.)

So, Trist definitely had connections. Otherwise. . . the man can best be described as a curmudgeon with a heart of gold. He was tall (6 ft.), skinny, sickly, stubborn, whiny, and hated to take orders.

Trist was given the secret draft of a treaty that asked for all of Mexico's northern territories. Clearly, even though the war wasn't over, the U.S. expected to win. Trist traveled south under an assumed name, and in New Orleans he booked passage on a ship to Mexico.

During his trip, Trist wrote long, long letters (up to 30 pages long) to Washington and his superiors about . . . nothing, really. Arriving in Veracruz, Mexico, he quarreled with the U.S. military commander in Mexico, General Winfield Scott, and made no progress on his mission. Things did not look good.

In late summer 1847, Trist finally patched things up with Scott and began negotiations with Mexican officials. Dispatches took 3 or 4 weeks to get to Washington, so Trist was pretty much on his own. The Mexicans balked at giving up so much land (1.2 million square miles!). As far as they were concerned, California, south of Monterey, was not on the bargaining table. They presented an alternate settlement, which Trist dutifully sent along to Washington, and talks broke off.

Fighting resumed, and Scott attacked Mexico City and captured it. The government collapsed, General/President Santa Anna fled, and the city surrendered.

Before news of this reached Washington, President Polk wrote and ordered Trist to return home. He thought nothing was being accomplished, and that Trist was incompetent. Then he got the Mexican version of the treaty and really exploded! Trist had embarrassed his country by even touching this ridiculous document! Polk sent another dispatch, recalling Trist.

But letters took up to a month to make the journey between Washington and Mexico, remember. When Trist received the president's first recall it was already November. Trist reacted as only he could: he sat down and wrote a 65-page letter, justifying every action he had taken.

Trist had already reopened negotiations with the new government of Mexico. Neither of the recall letters mentioned a replacement. As cranky as Trist was, his sense of integrity took over. He had seen war and bloodshed, and he hated it. Mexico was in chaos. Peace had to be made. He ignored the president's recall.

Polk was beside himself. He informed the military that Trist no longer represented the United States. By now, with Mexico so soundly defeated, he thought to add Baja California to the demands. But he never sent another negotiator, and Trist kept plugging away at the crafting a treaty.

Trist stayed with the original draft, which set the boundary of Mexico south of San Diego Bay in California, west to the Rio Grande. Mexico would have to accept the loss of Texas and cede the "New Mexico" territory (which covered all the states listed in the first paragraph) to the U.S. In return, Mexico would be paid $15 million. (The original draft authorized Trist to pay up to $20 million.)

The Treaty of Guadalupe Hidalgo was signed on January 25, 1848. It took its name from an old city which became a neighborhood of Mexico City, where the shrine of the Lady of Guadalupe was located. And for all Polk's anger, the Senate approved it on March 10, with only one major change: Article X (10) guaranteeing land ownership was removed.

And that's how the border got set where it is today.

Poor Trist left Mexico under military arrest, and was fired from the State Dept. The president refused to pay him for his service. He had concluded what may have been the most important treaty of the 19th century, but he was disgraced. Trist's own stubborness saw him through these dark days: he knew he had saved thousands of lives by averted further war. He knew he had brought his country the best treaty that could be had.

23 years later, Trist--nearly impoverished--was finally awarded the money he'd earned for his work, $14, 559.90. He died of a stroke four years later.

(Robert M. Ketchum wrote an article about Trist's work on the treaty for American Heritage called "The Thankless Task of Nicholas Trist." There's also a book on him by Robert Drexler titled Guilty of Making Peace.

The treaty itself can be read at the Library of Congress's website.