Agrarianism is a political and social philosophy which promotes the rights and sustainability of small farmers and poor peasants against the wealthy in society. Agrarianism supports farming as the only independent and self-sufficient profession, believes that capitalism and technology destroy independence and dignity and foster vice and weakness, promotes an egalitarian society based on the agrarian fellwoship of labor and co-operation, and believes in the spiritual importance of farming and working the land. Agrarianism in the United States was championed by Thomas Jefferson and his classical liberal Democratic-Republican Party, which believed that farmers were "the most valuable citizens" and the "truest republicans", and challenged urban aristocracy and corruption. Likewise, anti-capitalist "agrarian socialism" became a popular movement in late 19th-century Russia and early 20th-century Mexico, championed by Emiliano Zapata during the Mexican Revolution. This ideology became an important component of the Maoist school of communism during the mid-20th century, but the Great Chinese Famine of 1959-1962 - caused by the failed Great Leap Forward - killed between 15 and 30 million Chinese peasants due to Mao Zedong's mismanagement of the agricultural sector. Likewise, the communist leader Pol Pot's attempts to de-urbanize Cambodia and return its agricultural society to "year zero" was accompanied by the Cambodian Genocide, which massacred opponents of Pol Pot's societal reforms.