As a young teenager, he was forcibly recruited in 1814 by the ruthless Spanish General José Tomás Boves from the ranks of the defeated independence forces that had been abandoned by a fleeing Simón Bolívar at the city of Valencia.

When still a young man, he fought for the Spanish at the Battle of Queseras del Medio (1819) and Carabobo (1821) against the forces for independence led by Simón Bolívar, José Antonio Páez and others.

After the war, López continued to serve the Spanish government in several administrative posts, including the Cortes for Seville and as military governor in Madrid.

He made contact with influential American politicians, including John L. O'Sullivan, an expansionist who coined the term "manifest destiny."

However, US President Zachary Taylor, who had renounced filibustering as a valid means of US expansion, took steps against López and ordered his ships to be blockaded and seized.

[2][3] López, his aide-de-camp Ambrosio José Gonzales, and most of the filibuster leadership were Freemasons who relied extensively on the international fraternity to accomplish their plans.

He solicited the military help of Senator Jefferson Davis, who had distinguished himself in the Battle of Buena Vista, by offering him $100,000 and "a very fine coffee plantation."

Much of the local population joined the Spanish against López, and he hastily retreated to Key West, where he disbanded the expedition within minutes of landing to avoid being prosecuted under the Neutrality Act of 1794.

Had he been successful, López could have profoundly altered politics in the Americas by giving a strong Caribbean foothold to the United States and spurring its further expansion.

Faced with the inability of slavery to move southward, many Southerners turned away from expansion and talked instead of secession, which led to the American Civil War.