The plan would fall well short of the 80,000 troops that Army Gen. Stanley McChrystal, the top U.S. military commander in Afghanistan, suggested as a “low-risk option” that would offer the best chance to contain the Taliban-led insurgency and stabilize Afghanistan.

It splits the difference between two other McChrystal options: a “high-risk” one that called for 20,000 additional troops and a “medium-risk” one that would add 40,000 to 45,000 troops.