John C. Crittenden of Kentucky were important border state Whigs who were influential in the Taylor administration. Supreme Court Justice John McLean of Ohio commanded a following in the party and was a perennial aspirant for the Whig presidential nomination, but he maintained his independence from the party and never ran for office as a Whig candidate. Thomas Corwin of Ohio emerged in the 1840s as a leading opponent of the Mexican–American War, and he later served as Fillmore's Secretary of the Treasury. William Cabell Rives of Virginia joined the Whig Party over dissatisfaction with Van Buren's handling of the Independent Treasury, and he became a prominent conservative Whig. In Georgia, future Confederate Vice President Alexander H. Stephens and Robert Toombs competed for influence with their intra-party rival, John M. Berrien. Future Republican President Abraham Lincoln served a single term as a Whig congressman representing Illinois. One strength of the Whigs was a superb network of newspapers—their leading editor was Horace Greeley of the powerful New-York Daily Tribune. The Boston Atlas, under the leadership of Richard Haughton and Richard Hildreth, also emerged as an important Whig paper. Influenced by the writings of Thomas Malthus and David Ricardo, Henry Charles Carey became the leading Whig economist in the 1830s. Other prominent Whig-aligned intellectuals and public figures include journalist John G. Palfrey of the North American Review, novelist John P. Kennedy, and historian William H. Prescott. Factions The Whigs suffered greatly from factionalism throughout their existence as well as weak party loyalty that stood in contrast to the strong party discipline that was the hallmark of a tight Democratic Party organization. Forged out of opposition to Jackson's perceived executive tyranny, the early Whig Party was divided between former National Republicans who favored federal measures to promote economic development and Southern states' rights advocates who wished to keep federal intervention in the economy to a minimum. By the 1840s, Southern Whigs like John M. Berrien of Georgia and John Botts of Virginia endorsed interventionist measures, but other Southern Whigs like William Cabell Rives of Virginia actively sought to shift the party away from economic nationalism. The Whig Party faced persistent sectional divisions regarding slavery. Northern Whigs tended to be more anti-slavery than Northern Democrats, but during the 1830s Southern Whigs tended to more pro-slavery than their Democratic counterparts. By the late 1840s, Southern Democrats had become more insistent regarding the expansion of slavery,