The highest ranking military officer in the US, General Martin Dempsey, Chairman of the Joint Chiefs of Staff, warned that further involvement in Syria could cost over a billion US dollars a month.
In an open letter to US senators, Dempsey outlined potential for US military involvement in the Syria conflict, assessing the risks and costs of such action.
Dempsey wrote that the 'risks' of training, advising and assisting the opposition included "extremists gaining access to additional capabilities, retaliatory crossborder attacks, and insider attacks or inadvertent association with war crimes due to vetting difficulties."
The General also said that the cost of conducting limited stand-off strikes would be in the billions and posed the threat of "retaliatory attacks" and "a probability for collateral damage impacting civilians and foreigners inside the country."