Story highlights Martin McGuinness, a former IRA commander, resigned from the Northern Ireland Assembly

His move strains the fragile power sharing agreement

Ruth Dudley-Edwards is an Irish historian, broadcaster and journalist, writing regularly for the Irish Sunday Independent and the Belfast Telegraph. She is also a biographer and novelist. The opinions in this article belong to the author.

(CNN) Martin McGuinness, a former IRA commander, and, until Monday, Deputy First Minister of Northern Ireland, has resigned, forcing elections in the Northern Ireland Assembly.

It is only eight months since the previous election when his party, Sinn Fein, came second to the Democratic Unionist Party (DUP), whose leader, Arlene Foster, became First Minister. Because of McGuinness's decision and the power sharing nature of the Assembly, she also loses her post.

This dramatic event will cause concern for many due to the fragile political situation in Northern Ireland, where the two parties share power, despite having bitterly opposing politics steeped in the country's history of sectarian violence.

Leader refuses to step down

The incident which has led to his resignation is a scandal over the Renewable Heat Incentive scheme, which was so badly conceived and executed by the department of which Foster was then the minister responsible, that it looks likely to cost taxpayers millions.

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