The UN desperately wants to send troops to Darfur. Ok, lets make the debatable assumption thats a good idea. But lets just look over the facts regarding implementation.
A quick review a few features of countries recently in which western forces have helped establish and keep the peace (in reality : benign occupations)
Population ~ 25million (Concentrated in narrow strip along the two rivers)
Area ~438 000 sq km, desert and two rivers
Access excellent via Kuwait (excellent existing ports and staging infrastructure), major airport Baghdad, NATO neighbor Turkey, good existing road infrastrucutre with major highways
Number of NATO forces to occupy : ~ 150 000+
Population ~ 2,5 million (concentrated in central large valley)
Area ~10 000 sq km, valley surrounded by mountains
Access limited but via FYROM, close to NATO countries Greece (ports), Italy (air), major airport Pristina, good existing road infrastructure
Number of NATO forces to occupy : ~40 000
Population : ~ 4,5 million (concentrated in valleys)
Area : ~50 000 sq km, mountainous as hell
Access limited, but next to developed Croatia (ports Split, airport, close overland access from NATO member Hungary, railheads), major airport Sarajevo, poor existing transport infrastructure (mainly a bridge problem)
Number of NATO forces to occupy : ~ 60 000
Population : ~ 6 million (all over the shop)
Area : ~ 500 000 sq km, desert and savannah
Access hopeless, no rail, no port access, little existing road network, no airhead, no friendly/developed countries adjacent
Number of NATO forces required to successfully occupy (base guesstimate from area and population from previous examples): 80 000 - 100 000?
The size of force to successfully enforce peace in Darfur is large, as the area is huge but it is without infrastructure. The lack of roads demands many off terrain vehicles (jeeps and multi-wheeled APCs) and helicopters if the force is to be mobile at all. Worse, it is far, far from anywhere that can provide support for even minor but important stuff like bottled water or food or fuel, and there is no port of debarkation to be seen. A local APOD could be developed from near zero, but there is no SPOD, and will be none ... ever. Neither is there a railhead. Note that the baselines are western (NATO or near equivalent) forces - I have no belief in African peacekeepers doing much other than spreading AIDS.
Moral of the story : it is not going to happen.
Even if the forces are available (and they are not), the logistical challenge of maintaining forces without rail or sea access, without adjacent host nation services, in an area without infrastructure worth a damn, is just too daunting for words.
The UN can send some forces, but it is unlikely they will be of sufficient size, quality (African) or leadership (UN) to fix anything that isn't already fixed locally.
And so Sun Tzu might say : So much for peace enforcement in Darfur.