Sri Lanka's way was genocide. In 2009 , tens of thousands of Tamil civilians took shelter in Red Cross designated safe zones. The Red Cross gave the coordinates of the safe zone to the Sri Lankan military so that the military would know where not to bomb. The Sri Lankan military used the coordinates to unleash artillery on the safe zone where the civilians were all seeking refuge, killing over 40,000.
The Sri Lankan civil war is not an apt comparison because the majority ethnic group in Sri Lanka started a pogrom on the minority Tamils, which is what started the civil war. The Sri Lankan was waging a scorched earth policy, torture, disappearances, and killings of civilains from the start. They only won in the end because the ethnic minority ran out of people to bear arms and neighboring countries all supported the Sri Lankan government. The only reason the Taleban is able to kill coalition forces and capture ground is because the Pakistan government and society supports them. Without the Pakistani support the Taleban would have long been destroyed. ISIS got soo strong because they had support from Turkey, Saudi Arabia, Qatar, other GCC countries and Iraqi Sunnis. When ISIS lost its international support and some Sunni tribes turned against them, they lost. MArmed groups need local allies and other nations to support them.
The US has been spending decades killing and imprisoning drug dealers and not a dam thing was achieved. Trying to kill off drug dealers and manufactuers is like trying to outlaw alcohol. Just legalize it for adults . Adults should have the right to consume dam near anything they want , that is what freedom is about.