President Jefferson could no longer overlook the adventures of Burr and his friends. He knew that very little was needed to kindle the flame of war on the Mexican border. But he had his hands full with foreign affairs; England was making trouble for American sailors, and Napoleon was setting the whole world by the ears. So the busy President wrote to his agents in the West and urged them to keep a secret watch over Colonel Burr and Blennerhassett Island.
War with Spain almost came that summer. There were many disputed boundary lines between the United States and the Spanish colonies. The Spanish troops in Florida, Texas, and Mexico were prepared for an attack from the United States, and Spanish agents were urging Indian tribes to rise against the white men. Men protested in Western cities and towns. The people of Orleans Territory were afraid that Spain was going to try to win back their country by force of arms. On the 4th of July, 1806, the people of New Orleans held a great patriotic celebration, and in the evening a play called, "Washington; or the Liberty of the New World," was acted to a huge audience. Even the Creoles, who were more Spanish than Anglo-Saxon, were eager to fight against the old tyranny of Spain.
In the midst of this war excitement word came that a man born in Venezuela, named Francesco Miranda, had sailed from New York to free his native country from Spanish rule. Miranda was looked upon as a hero and patriot by many people in the United States, and this encouraged Burr and his friends.
There were in 1806 about one thousand soldiers in Texas, which was then a province of Mexico. These troops were ordered to cross the Sabine River, which formed a part of the disputed boundary, and as soon as they did cross the governor of Louisiana called for volunteers, and the people of Mississippi Territory prepared to march to the aid of New Orleans. The meeting place of the volunteers was Natchitoches, and there hundreds of countrymen came flocking, armed, and eager to defend Louisiana. Everything seemed ready for Aaron Burr to launch his great adventure. But at this point Burr's former friend, General James Wilkinson, the governor of Louisiana, changed his mind as to the wisdom of Burr's schemes. He would not give the order to the volunteers to march to the Mexican border, but waited, hoping that President Jefferson would prevent the war by diplomacy, or that the Spanish troops would decide to retreat.
On September 27th a great crowd in Nashville hailed Colonel Burr as the deliverer of the Southwest, and Andrew Jackson proclaimed, "Millions for defense; not one cent for tribute;" and at the same time the Mexican General Herrera ordered his troops to retreat from the River Sabine. Danger of war was over, and the moment the flag of Spain left the Louisiana shore, Burr's dream of an empire for himself and his friends vanished.
General Wilkinson knew that the government in Washington was suspicious of Aaron Burr's plans, and he thought that his name was included among those of Burr's friends. Some newspapers had even linked their names together, and the general, knowing perhaps the treachery of his own thoughts, now decided to prove his patriotism by accusing Aaron Burr and the others of treason. All the time that he was making a treaty with the Mexican general on the Texan frontier he was also working up a strong case against Burr. He saw to it that the agents put all suspicion on the shoulders of the others, and made him appear as the one man who had tried his best to protect his country. He intended to show that not only was he not a traitor, but that he was able to unmask traitors, by having pretended to join with them earlier.
In his sudden eagerness to prevent war with the Mexicans, General Wilkinson made terms of peace with them, which proved a great disadvantage to the United States at a later date, but which pleased the peace party of the day. He met the Mexican general at the very time when Burr and his allies were ready to launch their fleet of boats on the Mississippi River. Then Wilkinson made haste to raise the cry of "Treason in the West," which was to echo through the United States for months, and ruin the reputation of many men.
President Jefferson trusted Wilkinson, and when he heard the latter's charges against Burr he sent a special messenger to see what was happening at Blennerhassett Island. Before the messenger reached the Alleghany Mountains, however, another man had accused Burr in the court at Frankfort, Kentucky, of having broken the laws of the country in starting an expedition against Mexico. Burr said that he could easily answer these charges, and sent a message to Blennerhassett, telling him not to be disturbed. He went to the court at Frankfort, and when the man who had accused him could not bring his witnesses the matter was promptly dropped. Burr was more a hero than ever to the people of Frankfort. They agreed with a leading newspaper that said, "Colonel Burr has throughout this business conducted himself with the calmness, moderation, and firmness which have characterized him through life. He evinced an earnest desire for a full and speedy investigation—free from irritation or emotion; he excited the strongest sensation of respect and friendship in the breast of every impartial person present."
Burr then went back to Lexington, and continued raising money to buy a fleet of boats. Andrew Jackson had already received three thousand dollars in Kentucky for this purpose. Blennerhassett went on enrolling volunteers. It looked as if Burr's conduct at Frankfort had put an end to the rumors of treason.
General Wilkinson, however, was still anxious to make a name for himself as a great patriot, and he kept sending alarming messages to Washington. He accused his former friend of all sorts of treason. It was also perfectly clear that a large number of boats were being gathered on the Ohio under orders of Burr and his friends, and so President Jefferson sent word to the officers at Marietta to post one hundred and fifty or two hundred soldiers on the river to prevent Burr's fleet sailing. With the news of this order people in the West began to suspect their former hero, and even some of his old allies grew doubtful of his patriotism.