Although the word is “complex”, the answer is reasonably straightforward. The idea is that prior to 1999 the UN presence in the field was fairly fragmented. In many instances, the force commander operated independently—not totally independently, but independently—of other UN operations on the ground.
One of the great tragedies for Roméo Dallaire was that there was a political director on the ground who had a very, shall we say, distorted view of what was actually going on. General Dallaire had absolutely no support there. Also, the UN humanitarian and development operations had for a long time been run through a UN resident coordinator, but with no relationship to the military mission or to the political office.
One of the major recommendations of the Brahimi report in the year 2000 was the idea of a complex mission whereby all of the UN operations would work together and the mission would consist of specific pillars under a strategic plan, which would flow from the mandate as described by a Security Council resolution. The Security Council resolution would lay out all of the elements of a UN presence on the ground.
The development arms, which have voluntary funding rather than the assessed funding that peacekeeping and headquarters operations have—and if anyone wants to know the difference between those two things, I'm happy to explain—continued to operate quite a bit independently. It was a little difficult in the early years of the first decade of this century to get the development people to actually sit at the table with the political officers and the development officers.
The humanitarians too had a hard time with that. Humanitarians had been operating on their own, as I mentioned. They'd been out there on the front lines before the peacekeepers really started cranking up after 2000, and they were very reluctant to be seen in the company of peacekeepers, because although peacekeepers were neutral and international, the fact is that by various sides of the conflict they were seen as supporting the national interest, even if that wasn't the case. The humanitarians were thus used to negotiating their own way across enemy lines to deliver the goods.
Anyway, that's a complex matter that is never, ever really going to be totally solved.