In the summer of 1844, James K. Polk's political career was in ruins. As the Democratic National Convention approached, Polk had thought himself assured of the vice presidential nomination, but the presidential front-runner, former president Martin Van Buren, had made it clear that he had little interest in him. Van Buren was on a mission to regain the White House, which he had lost in 1840, and he needed a strong running mate. Polk had three strikes against him. First, Polk had been unable to deliver his and Andrew Jackson's home state of Tennessee in 1840, while Polk was governor. Second, he was fresh from having lost the governor's mansion—for a second time. And third, Van Buren—as well as the Whigs' candidate, Henry Clay—had just taken a stand against the annexation of Texas, whereas Polk had come out in its favor.
But as the delegates assembled in Baltimore, Polk perceived a wave of public sentiment in favor of bringing Texas into the Union, and he rode that wave all the way to the nomination and eventually the White House—the first "dark horse" candidate to do so. Congress soon annexed Texas, and Polk continued to look west, becoming the champion of what was known as "manifest destiny." He settled the disputed Oregon boundary with Great Britain, extending U.S. territory to the Pacific Ocean, and waged war on Mexico in hopes of winning California and New Mexico. The considerably smaller American army never lost a battle, and the southwest territories became part of the United States in 1848.
At home, however, Polk suffered a political firestorm of antiwar attacks, particularly from the Whigs. Despite tremendous accomplishments in just four years—from pushing the westward expansion to restoring an independent Treasury to ushering in an era of free trade—"Young Hickory" left office feeling the sting of criticism and suffering from a stressful presidency that had taken a heavy physical toll. He died within three months of departing Washington. Fellow Tennessean John Seigenthaler traces the life and legacy of this president who, as Harry S Truman noted, "said what he intended to do and did it."