Peter Harrison, the firm's chief executive, told BBC News that the demonstration did not focus on efficiency, but rather a proof of principle.

BBC: Petrol from air: Will it make a difference?

The only principle that stands up to scrutiny, Mr Fried argues, is efficiency: states should take on anything they can handle more cheaply and with better results than the federal government.

ECONOMIST: Republicans are for states�� rights��when it suits them