"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...