The Poppy Purchase Solution

It is a well-known fact that insurgent operations in Afghanistan are subsidized by the opium trade. Even the Taliban which suppressed opium agriculture during its reign in the country is now feeding off its production, buying weapons and recruiting soldiers with the enormous flow of funds.
So how much money are we talking about here?
Best estimates place the total annual value of Afghan opium production in the $4 billion range of which only about 25% goes to the farmers who raise the offending poppies.
US efforts to eradicate opium production have not been successful nor have policing measures, trying to interdict traffic or arrest major traffickers. The Afghan government has not been willing to take measures to stop opium cultivation since so many farmers depend on it for their livelihoods. Replacing the lucrative poppy trade with saffron or other crops has also seen a less than stellar performance. Traffickers are withholding supplies to keep the price high – this fact proven by the fact that legal opium for morphine and other drugs costs much less than its illegal counterpart which is sold as heroin in the developed world.
What should be done?
It's very simple. The US should buy up all the opium in Afghanistan.
The war costs the United States over 40 billion dollars a year. An additional $1 billion to buy opium directly from the farmers (25% of the total annual value) would probably pay for itself in reduced supplies of money to insurgent forces and thus a reduced combat level in the country. Establishing economic links to poor Afghan farmers who account for about 70% of the population would also undercut Taliban recruitment efforts and give the farmers a stake in a successful UN mission. Illegal dealers would not be able to offer higher prices to the farmers, since they are already withholding supplies to keep the international price high, and in any case there is no way they could outbid the US which should be willing to go as high as $4 billion a year, still a pittance relative to the costs of waging war there.
The US could then destroy the product it received from the farmers and with their newly established contacts, slowly wean them away from opium production and into something less destructive internationally, such as hashish or how about llamas which are also very cute.
In this way the US and its allies could slowly win over the population, undercutting the insurgency's access both to weapons and to recruits, and buy its way out of a difficult and interminable war.