who was the u.s. president during the mexican – american war which idea did he support
James K. Polk Polk is considered by many the most effective president of the pre–Civil War era, having met during his four-year term every major domestic and foreign policy goal he had set. After a negotiation fraught with risk of war, he reached a settlement with the United Kingdom over the disputed Oregon Country, the territory for the most part being divided along the 49th parallel. Polk achieved a sweeping victory in the Mexican–American War, which resulted in the cession by Mexico of nearly all the American Southwest. He secured a substantial reduction of tariff rates with the Walker tariff of 1846. The same year, he achieved his other major goal, re-establishment of the Independent Treasury system. True to his campaign pledge to serve only one term, Polk left office in 1849 and returned to Tennessee; he died in Nashville, most likely of cholera, three months after leaving the White House.