The Luttwak argument. Its a good one in some cases.

The interference of the Western community and India on different occasions saved the bacon of both the LTTE (numerous times) and the gov’t (a few less times). Had we not slapped the arms embargo on Bosnia, who knows how sooner a Croat/Muslim pushback could have occurred to nip Serb designs in the bud? Had we not let the French interfere to save their Hutu friends in Rwanda, how much sooner could the genocide have been ended by the RPF?

The real question is what works in a sense that brings both sides together. Aceh was and seemed destined to continue to be a slaughterhouse. A few years after some pragmatic thinking by the government to actually address with actions (not words) those oh so impossible root issues of the separatists, and Aceh became a land of peace. I don’t think its the exception, I just think its the path far less travelled because of ideology, cold-blooded power relationships within armies, business figures, and governments, and the overarching need to be ruthless in such instances, which rarely works in the long run because ruthless and competent are usually not related in a campaign.
The Burmese military is a great example of this. The junta finally calmed down most of its ethnic cleansing in exchange for cutting in multiple warlords and militias in on a far greater pot of money in illegal trade, human slavery, and resource depletion. It now has just a few fronts left where 10 years ago it had a dozen or more.

Talk of victory for the Sri Lankan government is ill-advised and short-sighted. Unless they are willing to deport the Tamils on boats sent to Tamil Nadu, the Sri Lankans and their extremist Buddhist/nationalist policies will come to wish for the days of the LTTE once the new groups incubating in the camps take root in a few years, much more nihilist and less controllable than the LTTE was. Those Tamils are seething in refugee camps with no medical care, jobs, education or hope in sight, a far more pitiable group than the pampered Palestinians or exiled Rwandans and a guaranteed problem that the majority are all too willing to accept out of spite for the past few decades of LTTE brutality.

The tragic part is this is not a situation where the Tamils made outrageous demands. They merely wanted to be treated as a respected minority with rights to their language and some degree of autonomy. They were repeatedly lied to and brutalized in the 50′s, 60′s and 70′s. They tried to use non-violent resistance and non-cooperation campaigns after that, but the torture and killing just continued. The LTTE emerged by killing the more open-minded and pragmatic survivors of the government’s crackdown and oppression, and the Sri Lankan people and their Tamil brothers and sisters were granted decades of war and suffering as a result. What will be Pt. 2?

“…the Sri Lankan military did what they wanted and the world met them with flat indifference”

Is the answer for COIN by US allies / proxies to (1) send the US uniformed military home, (2) accept quiet or clandestine support from the USA which does not get reported in the US media since no (admitted) US casualties are occurring, and (3) get a green light from the USA to use Sri Lankan methods to crush the insurgency (just keep us out of it — publicly)?

Would that be faster, cheaper, more effective?

Might it even be more humane overall if the war was shorter, the grinding down of civil society was lessened, and fewer people got killed overall?