In 1879 he was prominent enough in Irish nationalist circles to be a committee member and propose the election of Charles Stewart Parnell as president of the Irish Land League. In 1880 he visited Minnesota and became involved with Bishop Ireland's scheme to settle poor Irish people in the State, recently vacated by the Eastern Dakota. On 27 December 1881 The Times published an article from 'a correspondent' about 'An Irish Colony. Currie, Murray County, Minnesota'. The article explained that John Sweetman was the Managing Director of the Irish-American Colonization Company, "the principal organizer and practical director of the emigration...in order to make the most profitable selection of lands Mr Sweetman travelled through and carefully examined the States of Dakota and Minnesota, and also Manitoba, and finally purchased some 20,000 acres of prairie land situated in Murray County...". Unfortunately the colonisation project was not a complete success, but it did help a number of people to obtain a better life in America. The Sweetman brewery in Dublin was purchased by Casey's Drogheda Brewery Ltd in 1890. He was a major investor in the National Press newspaper. The Times of 3 June 1892 mentioned that "Mr John Sweetman of County Meath, who had contributed £1,000 as a donation to the fund for starting the National Press, had been unanimously selected for the Eastern Division". This was at a convention to select Nationalist candidates for the two Parliamentary constituencies in County Wicklow. He was elected at the 1892 general election as MP for East Wicklow as a member of the Anti-Parnellite faction of the Irish Parliamentary Party. He became a Parnellite in 1895 and resigned the seat on 8 April 1895. At the resulting by-election 26 April 1895, he stood as a Parnellite candidate but was defeated in a closely fought three-way contest. At the general election in July 1895 he stood in North Meath, where he narrowly failed to unseat the sitting anti-Parnellite MP James Gibney.
Radicalisation
By the early twentieth century he had become more radical. In 1905, speaking at the annual conference of the Catholic Truth Society of Ireland in response to a paper suggesting the replanting of the waste lands of Ireland as a remedy to emigration, he displayed considerable hostility to the "English" government. The Times reported that he said "it was not for that society to call upon its greatest enemy, the English government, to plant forests. The English government hated the Irish nation as that of Egypt hated the Jewish nation, and they must fight the Government with all the weapons that God had given them, just as Moses had fought the Egyptians. Unfortunately they had not the power to call down the ten plagues of Egypt upon the English Government, but they could boycott England's manufactures and her Navy and Army". He was one of the founders of Sinn Féin in 1905. He became the party's second president in 1908, succeeding Edward Martyn, and retained the presidency until 1911 when he stepped down, to be succeeded by Arthur Griffith. He was briefly arrested and detained after the 1916 Easter Rising. He turned down a Sinn Féin nomination for the 1918 general election on the grounds that he was too old; his cousin Roger Sweetman was Teachta Dála for North Wexford from 1918 to 1921. Sweetman supported the Pro-Treaty faction in the Civil War period but later denounced the government of W. T. Cosgrave for its abandonment of Griffith's protectionist economic policies, and supported Fianna Fáil after 1927. Throughout his life he wrote many letters to Irish newspapers, and in the late 1920s and early 1930s he was a contributor to The Leader edited by D. P. Moran. Sweetman was fiercely opposed to the Blueshirts, comparing Eoin O'Duffy to Hitler. He also opposed plans to build a Catholic Cathedral in Merrion Square, where he himself lived, on the grounds that this would cause great trouble and inconvenience to the residents. He died in Dublin in 1936 aged 92.
