The brutal murder of an unarmed man in a Belfast pub by members of the IRA in January – coming only weeks after the IRA's robbery of the Northern Bank – provoked a wave of outrage and demands for the disbanding of the IRA. The international campaign for the prosecution of the killers mounted by the family of Robert McCartney, and the unprecedented criticism of the IRA in republican areas which followed, has placed Sinn Féin under intense pressure. On 6 April, after two months of sustained criticism, its president Gerry Adams publicly appealed to the IRA to embrace “purely political and democratic activity” in a speech described by Martin McGuinness – who, like Adams, is widely assumed to be a member of the IRA's ruling army council – as a “defining moment” in republican history. Once again, there is talk of seismic shifts, lines in the sand, end-games and other clichés which have long since numbed all but the most determined observers of the never-ending peace process into a dull stupor. Some are more sceptical, particularly given the fortuitous coincidence of the announcement with the beginning of the general election campaign. Since the 1990s the political landscape of Northern Ireland has seen more than its fair share of turning points and historic breakthroughs accompanied, at the same time, by increasing sectarian tensions and political polarisation. John Hume and David Trimble may have won Nobel prizes for their leadership, but their moderate parties have failed to hold on to their electorates.

Observers who take a long view of Irish republicanism have pointed out that the McCartney murder would not be the first such outrage to be viewed as a turning point in the history of physical force republicanism. The most obvious historical precedent is the shocking murder of Kevin O'Higgins on 10 August 1927, who was killed by three (similarly 'unauthorised') IRA men who chanced upon the Minister for Justice as he strolled home from Sunday mass. The repercussions of this dramatic event did, indeed, contribute to the transformation of the Irish political landscape, during a period of much greater political instability, just four years after the end of the Irish Civil War.

Backed by an outraged public, W.T. Cosgrave's Cumann na nGaedheal government introduced emergency legislation giving de Valera's abstentionist party, Fianna Fáil, little choice but to enter the Free State parliament, thereby accepting the legitimacy of a political settlement which republicans had vowed to destroy since the Anglo-Irish Treaty of 1921. By 1932, Fianna Fáil had been elected to power by an Irish electorate which had refused to endorse physical force methods but clearly supported the peaceful attainment of republican objectives. In 1936, de Valera – then in the midst of implementing a series of reforms which would transform the Free State into a republic in all but name – turned the forces of the State against his former IRA comrades. By the end of the Second World War, de Valera's government – having executed six republicans, allowed three to die on hunger strike, and interned hundreds more – claimed to have taken the gun out of Irish politics.

Although the parallels between the political journeys taken by physical force republicans in the 1920s and the past decade are striking, closer inspection reveals a more complex picture. A comparison of both periods demonstrates, first, that Fianna Fáil's path towards constitutional politics was not as smooth as is now assumed, and, second, that Gerry Adams has faced much greater difficulties than his predecessor in steering republicanism towards purely political methods. It also offers clues as to why the current Provisional leadership, which sees itself as the vanguard of a radical movement of the people, has been so reluctant to do what would clearly be very popular within its own community: disband the IRA and share power in government.

A useful starting point is to compare the journeys made by de Valera and Adams from the high ground of republican purism to the murkier byways of constitutional compromise. Superficially, the similarities are striking. De Valera, as president of Sinn Féin in the mid-1920s, and Adams, as president of Sinn Féin in the mid-1980s, found themselves in essentially analogous positions: both led parties which were firmly opposed to participation in the structures of the States in which they operated. Both leaders were more keenly aware than their followers that continued IRA violence and political abstention would bring little reward, instead serving to reinforce their political isolation. As leaders of movements which admired militaristic values and traditionally regarded political compromise with a certain degree of suspicion, both faced similar difficulties in persuading their supporters of the merits of the political path. In particular, both had to contend with the fact that the logical outcome of any such process – the acceptance, and thus implicit endorsement of, a partitionist settlement which owed its legitimacy to a British act of parliament rather than the First Dáil[Editor’s note: Irish Parliament] elected by the Irish people in 1918 – was regarded by many of their followers as a betrayal of republican principles.