Donnelly entered politics, now a
Republican, with two unsuccessful campaigns for the state legislature (1857, 1858). Despite not being elected, Donnelly was recognized as a highly effective political speaker, which led to a successful campaign for lieutenant governor, a position he held from 1860 to 1863. He was a
Radical Republican Congressman from Minnesota in the
38th,
39th, and
40th congresses, (1863–1869), a state senator from 1874 to 1878 and 1891–1894 and a state representative from 1887 to 1888 and 1897–1898. As a
legislator, he advocated extending the powers of the
Freedmen's Bureau to provide education for freedmen so that they could protect themselves once the bureau was withdrawn. Donnelly was also an early supporter of
women's suffrage. After leaving the Minnesota State Senate in 1878, he returned to his law practice and writing. In 1877, Donnelly spoke at a meeting of 10,000 people where he read his preamble to the
People's Party conference platform. The document of 12 short paragraphs, as altered slightly for the first nominating convention in Omaha that July, was the pithiest and soon became the most widely circulated statement of the Populist credo. Donnelly discussed corruption within politics and voting, and newspapers that distributed false and biased material. He stressed that Populists needed to take back their own country. In 1882, he published
Atlantis: The Antediluvian World, his best-known work. It details theories concerning the mythical
lost continent of
Atlantis. The book sold well and is widely credited with initiating the theme of Atlantis as an
antediluvian civilization that became such a feature of popular literature during the 20th century and contributed to the emergence of
Mayanism. Donnelly suggested that Atlantis, whose story was told by
Plato in the dialogues of
Timaeus and
Critias, had been destroyed during the same event remembered in the Bible as the
Great Flood. He cited research on the ancient
Maya civilization by
Charles Étienne Brasseur de Bourbourg and
Augustus Le Plongeon, claiming that it had been the place of a common origin of ancient civilizations in Africa, especially
ancient Egypt, Europe, and the Americas. He also thought that it had been the original home of an
Aryan race whose red-haired, blue-eyed descendants could be found in Ireland. Donnelly wrote that
Ireland was the
Garden of Phoebus (Hyperborea) of the
Western mythologists. A year after
Atlantis, he published
Ragnarok: The Age of Fire and Gravel, in which he expounded his belief that the Flood, as well as the destruction of Atlantis and the extinction of the mammoth, had been brought about by the near-collision of the Earth with a massive comet. This book also sold well, and both books seem to have had an important influence on the development of
Immanuel Velikovsky's controversial ideas half a century later. In 1888, he published
The Great Cryptogram in which he proposed that
Shakespeare's plays had been
written by Francis Bacon, an idea that was popular during the late 19th and early 20th century. He then traveled to England to arrange the English publication of his book by
Sampson Low, speaking at the Oxford (and Cambridge) Union in which his thesis "Resolved, that the works of William Shakespeare were composed by Francis Bacon" was put to an unsuccessful vote. The book was a complete failure, and Donnelly was discredited. Donnelly also made several other campaigns for public office during the 1880s. He made a losing campaign for Congress, this time as a
Democrat, in 1884. In 1887, he successfully campaigned for a seat in the Minnesota State Legislature as an independent. During this period, he was also an organizer of the
Minnesota Farmers' Alliance. In 1892, Donnelly wrote the preamble of the
People's Party's
Omaha Platform for the presidential campaign of that year. He was nominated for
Vice President of the United States in 1900 by the People's Party, also known as the Populist Party. The People's Party was a development of the National Farmers' Alliance, and had a platform that demanded the abandonment of the
gold standard and later for the adoption of
free silver, the abolition of
national banks, a
graduated income tax, a
direct election of senators, civil service reform, and an
eight-hour day. That year, Donnelly also campaigned for governor of Minnesota but was defeated. The People's Party protested the railroad companies corrupting government and advocated government regulation of the railroads. Donnelly had a key leadership role in this party, yet he received $10,000 from the Lake Superior and Mississippi Railroad Company. ==State park==