THE END of the hunger strike in Northern Ireland is a merciful event in itself, and it could mark a political turning point. Ten convicted terrorists of the Provisional Irish Republican Army had died since last May. Their stated purpose was to compel the British government to change their status from common criminal to political prisoner, this by way of advancing the IRA program to end British rule in Northern Ireland, unite its six counties with Ireland in the south, and impose an IRA regime of a type borrowing from both fascism and Marxism. British Prime Minister Margaret Thatcher stood firm, and compassionate pressures brought on the prisoners by their families eventually ended the strike.

In the general relief that this string of slow public suicides is at an end, another harsh prospect looms. The IRA may decide its leadership's militancy and its membership's morale need to be refurbished by a new show of terror. To be sure, IRA murders went on regularly while IRA suicides were going on, too. But a terror spectacular now is distinctly possible. The hunger strike churned Irish emotions, and there is no reason to believe the IRA is short on recruits for its ugly work. The danger may be aggravated by the extent to which the Thatcher government crows over the IRA's "defeat."

Terror or no, however, Mrs. Thatcher may face a rare political window of opportunity. It is not merely that she can now make certain overdue changes in prison procedure that she did not wish to make while under IRA duress but that should help keep the IRA from exploiting prison issues in the future. More important, she can renew her commitment to the process of political consultation on Northern Ireland that she had earlier undertaken with the Irish government in Dublin. There the government of Garret FitzGerald is poised and eager to be a partner in a new diplomatic enterprise.

Mrs. Thatcher has not been notably forthcoming on the Irish issue in the past. But good counsel is available to her from within her cabinet. If she chose to use this moment to make a fresh effort to get a political process going, one that would hold out at least some promise to Irish Catholics and to Irish Protestants, in the north as in the south, then it is possible she could engage energies that otherwise will curdle, or will generate further terror.