He was convicted of sedition for his part in the Young Irelander "Famine Rebellion" of 1848 but his sentence of death was commuted to deportation to Van Diemen's Land.

In 1837 Daniel O'Connell clashed with him over his opposition to the introduction of secret voting in elections and also Smith O'Brien's support for granting state payments to Catholic clergy.

[10] The objectives of the Confederation were "independence of the Irish nation" with "no means to attain that end abjured, save such as were inconsistent with honour, morality and reason".

[12] In the Confederation Duffy was trying to hold together a broad national coalition, and had for that reason advanced Smith O'Brien, as a Protestant and a landowner, to the leadership.

John Mitchel was convicted under new martial law measures approved by Parliament (including by a number of "Old Ireland" O'Connellite MPs).

In March 1848 Smith O'Brien and Thomas Francis Meagher returned from revolutionary Paris with hopes of French assistance.

[17] There was also talk of an Irish-American brigade and of a Chartist diversion in England[18] With Duffy's arrest, it was left to Smith O'Brien to confront the reality of the Confederates' domestic isolation.

Having with Meagher and John Dillon gathered a small group of both landowners and tenants, on 23 July Smith O'Brien raised the standard or revolt in Kilkenny.

[19] This was a tricolour he and Meagher had brought back from France, its colours (green for Catholics, orange for Protestants) intended to symbolise the United Irish republican ideal.

As Smith O'Brien proceeded into County Tipperary he was greeted by curious crowds, but found himself in command of only a few hundred ill-clad largely unarmed men.

They scattered after their first skirmish with the constabulary, derisively referred to by The Times of London as "Battle of Widow McCormack's Cabbage Patch".

[20] In Dublin on 5 June 1849, the sentences of Smith O'Brien and his confederates Meagher, Terence MacManus and Patrick O'Donoghue were commuted to transportation for life to Van Diemen's Land (Tasmania in present-day Australia).

The cottages which Smith O'Brien lived in on Maria Island and Port Arthur have been preserved in their 19th century state as memorials.

[22] Having emigrated to the United States, Ellis was tried by another Young Irelanders leader, Terence MacManus, at a lynch court in San Francisco for the betrayal of Smith O'Brien.

[24] But despite the efforts of George Henry Moore to recruit him as a leader of the Independent Irish Party,[25] Smith O'Brien played no further part in politics.