Here’s an interesting comparison from the US Army between the British handling of the Northern Ireland crisis between 1970 and 1999, and the French in Algeria 1957 to 1958. One of its conclusions, although it seems to ignore a lot of other factors is that the French gave their army a free hand to do whatever it had to win the struggle with the FLN (the Algerian Front de la Libération Nationale). It resulted in a near complete military victory, but:
The widespread, ruthless recourse to barbarity by forces that stood for “civilization” destroyed what legitimacy the French had among ethnic Algerians, and this had major political repercussions in France. By late 1957, clear evidence of torture and other government-sponsored or condoned forms of brutality and illegal behavior by the Army fed a popular outcry that grew until Charles De Gaulle was elected to the presidency in 1958, ending the Fourth Republic.
In contrast, by consistently attempting to hold to a legal and fully accountable prosecution of warfare, the British Government and military in Northern Ireland have retained the public’s mandate to prosecute the war and might yet see it to a successful conclusion. While such a strict adherence to the principles of law and legitimacy might considerably lengthen a campaign, the lessons of the long British experience in Northern Ireland suggest that a longer campaign might be the only way to ensure success.
Thanks to Jim for the heads up!