Polk's Plan

      Congressman John Slidell's mission to Mexico was very complicated and surrounded in mystery.  President Polk had sent Slidell to Mexico to negotiate two different plans.  The American and Mexican public were told that Slidell was to have Mexico agree on the Rio Grande as the border between Mexico and Texas.  Polk also ordered Slidell to offer Mexico $30 million for Alto California and Nuevo Mexico, roughly 50% of Mexico's territory.

     When Slidell and his staff arrived in Mexico City they found themselves in political limbo.  The President of Mexico Jose de Herrera was struggling to remain in power.  Herrera had negotiated peacefully with the United States in the past and because of this many Mexican officials were plotting overthrow him. If Herrera understood that if he  agreed to meet with Slidell it would jeopardize his power.  When word reached Mexico City that General Zachary Taylor had arrived in Texas with 3,550 soldiers, Herrera struggled to hold on to his office.

    News of Slidell's $30 million offer came out and caused a public outcry in Mexico.  Manu Mexicans saw the American offer as an insult and felt that the the intentions of the U.S. were clear: California was their goal. President Herrera was overthrown by General Mariano Paredes the commander of the Mexican army.   Slidell and his staff returned to the United States, where Slidell advised the President that it would be necessary to use force in order to get Mexico to negotiate peacefully.

    On March 3, 1846, General Zachary Taylor's forces arrived on the northern banks of the Rio Grande overlooking the Mexican town of Matamoros.  Taylor's men began to construct a fort along the river and began to prepare for a long siege.  From the other side of the Rio Grande, the residents of Matamoros observed as the Americans aimed their artillery at their town.  Taylor refused to meet with the commander of the Mexican army at Matamoros and ordered scouting missions along the river bank.

     After the disappearance of two U.S. soldiers, General Taylor increased the number of patrols in the area. On April 25, 1846, 1,600 Mexican calvary division attacked 63 U.S. soldiers on a patrol.  The fighting lasted a few minutes and ended with the deaths of 11 U.S. troops, six wounded,  with the rest taken captive.  When word reached General Taylor of the fight, he sent a message to President Polk that hostilities had occurred and that U.S. soldiers had died on American soil.

     Polk now had the justifiable reason to ask Congress for a declaration of war.