1792–1864, American statesman, vice president of the United States (1845–49), b. Philadelphia; son of Alexander James Dallas. He read law, was admitted (1813) to the bar, and was secretary to Albert Gallatin. After serving as solicitor (1815–17) of the Bank of the United States, Dallas was city attorney (1817–19) and mayor (1819) of Philadelphia. An active Democrat, he was appointed (1829) U.S. district attorney for E Pennsylvania, then served as a U.S. senator (1831–33), as attorney general of Pennsylvania (1833–35), and as minister to Russia (1837–39). He returned to his law practice, and a sharp political rivalry developed between him and James Buchanan in Pennsylvania. In 1844, Dallas was elected vice president on the Democratic ticket along with James K. Polk. Dallas was later appointed (1856) minister to Great Britain and was succeeded (1861) in that post by Charles Francis Adams. Dallas conducted the negotiations leading to the Dallas-Clarendon Convention, signed in 1856, which set a basis for the settlement of difficulties in Central America. He also secured from Great Britain a disavowal of the right of search, a historic matter of dispute. He wrote a biography (1871) of his father.
- See his letters from London (1869) and his diaries (1892) while a minister to Great Britain and Russia.