George Mifflin Dallas (July 10, 1792 – December 31, 1864) was an American politician and diplomat who served as mayor of Philadelphia from 1828 to 1829 and as the 11th vice president of the United States from 1845 to 1849. The son of Secretary of the Treasury Alexander J. Dallas, George Dallas attended elite preparatory schools before embarking on a legal career. He served as the private secretary to Albert Gallatin and worked for the Treasury Department and the Second Bank of the United States. He emerged as a leader of the "Family party" faction of the Pennsylvania Democratic Party, and Dallas developed a rivalry with James Buchanan, the leader of the "Amalgamator" faction. Between 1828 and 1835, he served as the mayor of Philadelphia, the United States Attorney for the Eastern District of Pennsylvania, and the Pennsylvania Attorney General. He also represented Pennsylvania in the United States Senate from 1831 to 1833 but declined to seek re-election. President Martin Van Buren appointed Dallas to the post of Minister to Russia, and Dallas held that position from 1837 to 1839. Dallas supported Van Buren's bid for another term in the 1844 presidential election, but James K. Polk won the party's presidential nomination. The 1844 Democratic National Convention nominated Dallas as Polk's running mate, and Polk and Dallas defeated the Whig ticket in the general election. A supporter of expansion and popular sovereignty, Dallas called for the annexation of all of Mexico during the Mexican–American War. He sought to position himself for contention in the 1848 presidential election, but his vote to lower the tariff destroyed his base of support in his home state. Dallas served as the ambassador to Britain from 1856 to 1861 before retiring from public office.