The US exit from Iraq at year's end leaves in place 30,000 fighters of Iran's Al Qods Brigades trained in elite guerilla warfare. At least half are disguised as private security personnel for Iraqi ministers and politicians in Baghdad, providing Tehran with a strong lever of manipulation. America's Iraq war therefore draws to a close as thousands of Al Qods operatives take up positions in the Green Zone, the Baghdad enclave built at great cost for US headquarters in Iraq.