(BBC News) During and after the Iraq war, many Army officers left because of the US military's gruelling pace. Now, officials are struggling with the consequences.
It is a March morning, cold and bright. The air smells like freshly mown grass at Fort Belvoir, Virginia, just outside Washington DC.
Inside a classroom in an old school, a red-brick building on Belvoir Road, blinds are pulled shut to keep out the sun.
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The classroom is filled with Iraq veterans, including Capt Jason Allen, a 31-year-old engineer with pale blue eyes and a boyish face.
He once looked for homemade bombs on roads in Anbar, a province where more than 1,300 American troops died.