A U.S. airstrike ordered by Afghan forces that inadvertently killed 22 people at a Doctors Without Borders hospital this weekend has amplified concerns that security forces are not ready to stand on their own two feet.

The turmoil in Afghanistan is presenting Obama with a painful choice: to go back on his promise to end the longest war in American history or press ahead with withdrawal over the advice of his top commanders.

“The most important calculation in the president’s decision is determining what is in the best long-term interest of the United States in that region of the world,” White House press secretary Josh Earnest told reporters Tuesday.

Obama is under pressure from Republicans and some Democrats in Congress to keep troops in Afghanistan past his withdrawal deadline of 2016; many fear the country, left to its own devices, would again become a safe haven for terrorist groups.