Lessons from Northern Ireland?
During the Northern Ireland "Troubles", starting in 1969 till the ceasefire now four years ago, the British Army deployed a large force, mainly infantry units to both rural and urban areas. Most of the army units were on short tours (from memory four months), and a smaller number were garrison units (on three year tours, i.e with families).
The Army developed a training system for pre-deployment, based in Germany and the U.K. with mock-up streets etc.
I do not recall criticism of the inability of infantry units to change role, although non-infantry units, e.g artillery, were deployed on short tours.
Remember at the start the Army took responsibility for policing (say 1969-1975). At one point around 30,000 troops were deployed; draining the main British Army in Germany.
Much was made of the impact of the training for junior officers and NCO's, including speaking to the press. Plus the adaptability of the British soldier.
Within the Army were two large regiments of military police, engineers (for searching), human and non-human intelligence gathering and small undercover units (SAS and recce).
On my bookshelf are a few tiltles (now dated):
Frank Kitson's Low Intensity Operations (1971) & Bunch of FIve (1977)
Mark Urban's Bog Boys Rules (1992)
Mark Hamill's Pig in the Middle (1985)
Tony Geraghty's The Irish War (1998)
Infantry unsuitable, rubbish! It is not the soldiers at fault, but the strategy used.
davidbfpo