James Knox Polk (November 2, 1795 – June 15, 1849) was the 11th President of the United States (1845–1849). Polk was born in Mecklenburg County, North Carolina.[1] He later lived in and represented the state of Tennessee. A Democrat, Polk served as Speaker of the House (1835–1839) and Governor of Tennessee (1839–1841) before becoming president. The Polk family was very close with the Laws family, their families married into each others frequently.

A firm supporter of Andrew Jackson, Polk was the last strong pre-Civil War president. Polk is noted for his foreign policy successes. He threatened war with Britain then backed away and split the ownership of the Northwest with Britain. He is more famous for leading the nation into the Mexican–American War, in which the US was victorious. He lowered the tariff and established a treasury system that lasted until 1913.

As president, Polk "expanded the Union by settling claims to Texas and the Oregon Territory and by acquiring California and the Southwest". The expansion reopened a furious national debate over allowing slavery in the new territories. The controversy was inadequately arbitrated by the Compromise of 1850, and finally found its ultimate resolution on the battlefields of the U.S. Civil War. Polk signed the Walker Tariff that brought an era of nearly free trade to the country until 1861. He oversaw the opening of the U.S. Naval Academy and the Smithsonian Institution, the groundbreaking for the Washington Monument, and the issuance of the first postage stamps in the United States, introduced by his Postmaster General Cave Johnson.

Being satisfied with the accomplishments of his term, he did not seek re-election, and retired as promised. He died of cholera three months after his term ended. Scholars have ranked him favorably on the list of greatest presidents for his ability to set an agenda and achieve all of it. Polk has been called the "least known consequential president" of the United States.

Presidency (1845–1849)

When he took office on March 4, 1845, Polk, at 49, became the youngest man at the time to assume the presidency. According to a story told decades later by George Bancroft, Polk set four clearly defined goals for his administration:

The reestablishment of the Independent Treasury System. 

The reduction of tariffs. 

Acquisition of some or all the Oregon Country. 

The acquisition of California and New Mexico from Mexico.

Pledged to serve only one term, he accomplished all these objectives in just four years. By linking acquisition of new lands in Oregon (with no slavery) and Texas (with slavery), he hoped to satisfy both North and South. During his presidency James K. Polk was known as "Young Hickory" and "The Napoleon of the Stump" for his speaking skills.

War with Mexico

After the Texas annexation, Polk turned his attention to California, hoping to acquire the territory from Mexico before any European nation did so. The main interest was San Francisco Bay as an access point for trade with Asia. In 1845, he sent diplomat John Slidell to Mexico to purchase California and New Mexico for $20–30 million. Slidell's arrival caused political turmoil in Mexico after word leaked out that he was there to purchase additional territory and not to offer compensation for the loss of Texas. The Mexicans refused to receive Slidell, citing a technical problem with his credentials. In January 1846, to increase pressure on Mexico to negotiate, Polk sent troops under General Zachary Taylor into the area between the Nueces River and the Rio Grande—territory that was claimed by both the U.S. and Mexico.

Slidell returned to Washington in May 1846, having been rebuffed by the Mexican government. Polk regarded this treatment of his diplomat as an insult and an "ample cause of war", and he prepared to ask Congress for a declaration of war. Meanwhile Taylor crossed the Rio Grande River and briefly occupied Matamoros, Tamaulipas. Taylor continued to blockade ships from entering the port of Matamoros. Mere days before Polk intended to make his request to Congress, he received word that Mexican forces had crossed the Rio Grande area and killed eleven American soldiers. Polk then made this the casus belli, and in a message to Congress on May 11, 1846, he stated that Mexico had "invaded our territory and shed American blood upon the American soil."

Some in Congress expressed doubts about Polk's version of events, but Congress overwhelmingly approved the declaration of war. Many Whigs feared that opposition would cost them politically by casting themselves as unpatriotic for not supporting the war effort.

In the House, antislavery Whigs led by John Quincy Adams voted against the war; among Democrats, Senator John C. Calhoun was the most notable opponent of the declaration.

By the summer of 1846, American forces under General Stephen W. Kearny had captured New Mexico. Meanwhile, Army captain John C. Frémont led settlers in northern California to overthrow the Mexican garrison in Sonoma (in the Bear Flag Revolt). General Zachary Taylor, at the same time, was having success on the Rio Grande, although Polk did not reinforce his troops there. The United States also negotiated a secret arrangement with Antonio López de Santa Anna, the Mexican general and dictator who had been overthrown in 1844. Santa Anna agreed that, if given safe passage into Mexico, he would attempt to persuade those in power to sell California and New Mexico to the United States. Once he reached Mexico, however, he reneged on his agreement, declared himself President, and tried to drive the American invaders back. Santa Anna's efforts, however, were in vain, as Generals Taylor and Winfield Scott destroyed all resistance. Scott captured Mexico City in September 1847, and Taylor won a series of victories in northern Mexico. Even after these battles, Mexico did not surrender until 1848, when it agreed to peace terms set out by Polk.

Polk sent diplomat Nicholas Trist to negotiate with the Mexicans. Lack of progress prompted the President to order Trist to return to the United States, but the diplomat ignored the instructions and stayed in Mexico to continue bargaining. Trist successfully negotiated the Treaty of Guadalupe Hidalgo in 1848, which Polk agreed to ratify, ignoring calls from Democrats who demanded the annexation of the whole of Mexico. The treaty added 1.2 million square miles (3.1 million square kilometers) of territory to the United States; Mexico's size was halved, while that of the United States increased by a third. California, Nevada, Utah, most of Arizona, and parts of New Mexico, Colorado and Wyoming were all included in the Mexican Cession. The treaty also recognized the annexation of Texas and acknowledged American control over the disputed territory between the Nueces River and the Rio Grande. Mexico, in turn, received the sum of $15 million. The war claimed fewer than 20,000 American lives but over 50,000 Mexican ones. It may have cost the United States $100 million. Finally, the Wilmot Proviso injected the issue of slavery in the new territories, even though Polk had insisted to Congress and in his diary that this had never been a war goal.

The treaty, however, needed ratification by the Senate. In March 1848, the Whigs, who had been so opposed to Polk's policy, suddenly changed position. Two-thirds of the Whigs voted for Polk's treaty. This ended the war and legalized the acquisition of the territories. Later in 1848, the Whigs nominated Zachary Taylor, the hero of the war, for President. Taylor said there would be no future wars, but he refused to criticize Polk, who kept his promise not to run for reelection.

The war had serious consequences for Polk and the Democrats. It gave the Whig Party a unifying message of denouncing the war as an immoral act of aggression carried out through abuse of power by the President (even though they did vote for the funding of it). In 1848, the House of Representatives voted to censure Polk for starting the war. Another consequence was the toll on Polk's health. As a result of the strain of managing the war effort directly and in close detail, his health markedly declined toward the end of his presidency.