I guess the Kachin are the outliers, because they're in heavy conflict right now. It may be taken by Burmese troops any day now, and everyone else is signing.
Starting a couple of years ago, all of the ethnic groups were trying to form this united ethnicities council so that they could negotiate en masse with the Burmese government. But there were differences among them and they weren't able really to jell in time to form a solid united body. The Burmese government started giving good deals and encouraging them to break apart.
I think there were a couple of reasons why Kachin happened. One is that they were never that happy with their ceasefire. The 2008 constitution, which we keep getting back to, didn't give them what they felt was proper representation in Parliament. In the 2010 election most of their political parties were banned from running, and even in the election in April, two Kachin political parties were not allowed to contest. They're pushing for fundamental changes to the 2008 constitution so that they can have more representation, and the Burmese are not agreeing to this at all right now.
The Burmese government is negotiating the ceasefires, not the army, and they have different individuals who are ceasefire negotiators. The man who has been working with the Karen and Shan and several other groups is the railroad minister, and he's seen more as one of the reformists. The guy who's negotiating with the Kachin is one of the hardliners, so there is less give and take there.
The flashpoint for Kachin was a series of hydroelectric dam projects in Kachin state. There are seven or eight of them, and the Kachin Independence Organization approved several. They're mostly run by the Chinese. But there was one that was going to flood a valley that would cut off the Kachin Independence Army 3rd Brigade from the rest, and the Burmese were building a big road for transport there that could also be used to deliver military troops and split the Kachin and take them over, so for security reasons they didn't want that dam.
As the dam was being built, the Burma army moved a lot of troops in there, and there are a lot of Kachin troops. When you have a lot of armed people in a small area, fighting is started and then it's continued.
I believe in the KIO's demands. They don't want representation just for themselves, they are arguing for all ethnic minorities. It's a big ask. There have been three rounds of ceasefire talks, and they're now debating on where they're going to have the next round. So things are still going on.
I guess there have been more progressive negotiators with other ethnic minorities, so that's part of the answer.