"The United States has appropriated and is obligated to spend an estimated $5.9 trillion (in current dollars) on the war on terror through the Fiscal Year 2019," the annual Costs of War project report said.
The figure differs substantially from the Pentagon's own estimates because it includes not only the direct spending in war zones in Iraq, Syria, Afghanistan, Pakistan and elsewhere but also the costs incurred by the entire federal government as a consequence of the wars, the report noted.
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The base estimate for war-on-terror spending during the 18-year period comes to $4.9 trillion, to which the report added $1 trillion to cover US obligations to pay for the care of post-9/11 veterans throughout their lifetimes.
Moreover, the report warned that costs are likely to be higher due to future interest costs since all of the money is borrowed.