The New Foreign Policy Yard Boss

When Barack Obama named Tom Donilon as his new National Security Adviser this month, he ticked off his aide's best-known qualities: a remarkable work ethic, a probing intellect and a limitless appetite for Diet Coke. But the President left out another Donilon attribute that will likely matter most in the coming year, when once again the subject of the Afghan war's direction is set to reach the Oval Office. "He looks out for the President," says one senior White House aide. (See the top 40 civic leaders under 40 years of age.)

In a city of lawyers, Donilon has long distinguished himself as a man who takes care of the client. He started as a political aide to Jimmy Carter, managing vicious floor fights at the 1980 Democratic convention. He later worked as a counselor for a string of Democratically inclined powerhouses: Senator Joe Biden, Secretary of State Warren Christopher, Chicago hotel heiress Penny Pritzker and the troubled mortgage giant Fannie Mae.

He entered Obama's orbit in 2008, leading the foreign policy debate prep sessions. For the past 18 months, he has been one of just a handful who attend the daily intelligence briefing, and he ran the powerful deputies committee on key foreign policy crises. (See the top 10 political prodigies.)

Donilon's biggest test will be keeping the Pentagon and the State Department in line when troop drawdowns from Afghanistan start in July 2011. There is no consensus on how quickly the pullout should proceed, but there is a good chance that the generals will balk at Obama's timetable. It will fall to Donilon to be the yard boss who keeps everyone on board and protects his sole client, the President, from overreach.

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