Re the IdN peacekeepers, could it be a predominant mix of Americans and Canadians?
2. I had dealings with the US military in the mid-late 1970s. It's hard to overstate just how incompetent the US military was during this period. This would be just outside that period, and they were improving, but we are not looking at the best soldiers in the world. US Military doctrine was based on the premise that the first shots won the battle, and that overwhelming firepower was the way to go. "Fire before they do" is going to have unfortunate consequences in a peacekeeping role.
Just the thought of US troops acting as peacekeepers in Northern Ireland during the period is enough to bring me out in a cold sweat.
Benn wouldn't turn to the US, and the UN wouldn't involve US troops, so it's a non-issue.