26. James Knox Polk
Polk was the most effective single term President in American history, achieving all of the goals which he emphasized during his campaign for the office, and then as promised declining to accept a second term. He achieved victory in the Mexican War, which led to the acquisition of most of the Southwest United States, resolved the Oregon boundary dispute with Great Britain, and re-established the independence of the United States Treasury. He also successfully argued for lower tariffs and signed into law the Walker Tariff law, which once enacted led to an economic upturn with increased trade with Great Britain and the rest of Europe.
