When the House of Representatives passed the National Defense Authorization Act last week, one of the unanswered questions hovering over the measure was how much money the Pentagon would need for the war in Afghanistan. At the time the bill passed, the Administration had not decided whether U.S. forces would remain in Afghanistan after 2014. As a result, there was no formal request to Congress for war funding, also known as overseas contingency operations funding or OCO.

What a difference a few days make. Tuesday, President Obama announced that he intended to leave a force of 9,800 in Afghanistan through 2014 with all forces returning back to the United States by 2016. Though smaller than the number of troops in that theater today, keeping a force of nearly ten thousand in the field will require significant resources. As a result, we can expect an OCO request coming to the Hill in the coming weeks.

While the OCO request will likely be less than the $85 billion that was appropriated for fiscal year 2014, the question is how much less. The number of troops on the ground is not the only cost driver for the OCO. The military services, most notably the Army, have used the OCO funds to pay for the reset of the force; this refers to the huge bill for replacing, and in some instances recapitalizing, the war torn equipment used in Iraq and Afghanistan over the past ten years.

In the past, Congress has been all too willing to pay for the reset costs in the OCO, but a recent amendment adopted in the House-passed version of the National Defense Authorization Act would place restrictions on the use of OCO funding. This language, if enacted, combined with a lower level of OCO funding could present a real obstacle for the military services which were banking on the OCO to pay for the reset bill and rebalance the force after a decade of war.