Back in the United States, Walker was tried in San Francisco in federal court for violation of United States neutrality laws and policies. Popular sentiment was still with him, however, and he was acquitted of all charges by a jury after only eight minutes of deliberations. He returned to his law practice, convinced that he would have succeeded if he had only had more men and supplies.
Within a year, he was back in action. Nicaragua was a rich, green nation that had one great advantage: in the days before the Panama Canal, most shipping went through Nicaragua along a route that led up the San Juan River from the Caribbean, across lake Nicaragua, and then overland to the port of Rivas. Nicaragua was in the throes of a civil war between the cities of Granada and León to determine which city would have more power. Walker was approached by the León faction (which was losing), and soon rushed to Nicaragua with some 60 well armed men. Upon landing, he was reinforced with another 100 Americans and almost 200 Nicaraguans. His army marched on Granada and captured it in October, 1855. As he was already considered supreme General of the Army, he had no trouble declaring himself president. In May, 1856, the Franklin Pierce administration officially recognized Walker's government.
Defeat in Nicaragua
Walker had made many enemies in his conquest. Greatest among them was Cornelius Vanderbilt, who controlled an international shipping empire. As President, Walker revoked Vanderbilt's rights to ship through Nicaragua, and Vanderbilt, enraged, sent soldiers to oust him. Vanderbilt's men were joined by those of other Central American nations, chiefly Costa Rica, who feared that Walker would take over their countries, too. In addition, Walker had overturned Nicaragua's anti-slavery laws and made English the official language, which angered many Nicaraguans. In early 1857 the Costa Ricans invaded, supported by Guatemala, Honduras, El Salvador as well as Vanderbilt's money and men, and defeated Walker's army (which had been thinned by disease and defections) at the Second Battle of Rivas. Walker was forced to return once again to the United States.
Back in the United States, Walker was greeted as a hero, particularly in the south. He wrote a book about his adventures, resumed his law practice, and began making plans to try again to take Nicaragua, which he still believed to be his. After a few false starts, including one in which US authorities captured him as he set sail, he landed near Trujillo, Honduras, where he was captured by the British Royal Navy. The British already had important colonies in Central American in British Honduras (now Belize) and the Mosquito Coast (in present-day Nicaragua) and they did not want Walker stirring up rebellions. They turned him over to Honduran authorities, who executed him by firing squad on September 12, 1860. It is reported that in his final words he asked for clemency for his men, assuming the responsibility of the Honduras expedition himself. He was 36 years old. His grave can still be visited in Trujillo.
Walker's dramatic story did inspire one movie, 1987's Walker, which received mixed-to-poor reviews. In the United States today he is seldom remembered outside of his native Nashville, which continues to be proud of its most famous son, even in today's age of political correctness.
He is better remembered in Central America, where his name is still a synonym for Yankee imperialism. He was responsible for the fame of Costa Rica's greatest national hero, Juan Santamaría, who died heroically during the Second Battle of Rivas.
It is difficult today to understand the situation that could create a man like William Walker. During the mid-1800's, the United States was spreading out, taking land from Mexico and anywhere else it could find it. Most Americans believed that it was Manifest Destiny, or God's will that the United States eventually own the entire continent. Most believed that even if men like Walker were distasteful, what they were doing was eventually in the best interest of everyone, including the natives of the countries they attacked, because they would eventually be better off with the "efficient and noble" American government in charge. As for Walker himself, if he had succeeded in acquiring statehood for Baja California, Nicaragua or Honduras he would almost certainly have been named governor and achieved a prestige similar to that of Sam Houston in Texas.
Because Walker is not very well known today, it is easy to lose sight of how close he came to succeeding and what the consequences may have been if he had. In Mexico, had he not lost his supplies, he may have succeeded in taking Sonora. If he had, it is almost certain that more men would have flocked to his banner, and it is entirely possible that today Baja California and Sonora would be part of the United States. In Nicaragua, if he had not angered Vanderbilt, he may have held onto Nicaragua, perhaps eventually even taking all of Central America. If any of these states had entered the United States as a pro-slave state, it may have tipped the delicate balance that existed between slavery and free states at the time and may have influenced the outcome of the Civil War, which would break out the year after Walker was executed.