The Pentagon’s undersecretary for policy, Michele Flournoy, intends to step down in early 2012 to spend more time with her family after serving three years in the job, Defense Secretary Leon Panetta said yesterday.

“Michele made clear that her decision to leave is motivated by personal and family considerations,” Panetta said in a statement. “I am very pleased that she has agreed to stay on until early next year to enable a smooth transition.”

Panetta credited Flournoy for guiding strategy in Afghanistan and Iraq, outlining the department’s priorities and global posture in 2010’s Quadrennial Defense Review and this year’s strategic review.

“Michele has made a strong and lasting positive imprint on this department and on our nation’s security,” Panetta said.

The Senate confirmed Flournoy as undersecretary in February 2009. In the two years before that, Flournoy had been president of the Center for a New American Security.