Washington, D.C. ? President Barack Obama’s top advisers are depicted in a new book as arguing over much of the past 20 months about policy and turf, with some top members of his national security team doubting the president’s strategy in Afghanistan will work.

The book, “Obama’s Wars,” by journalist Bob Woodward, says Obama aides were deeply divided over the war in Afghanistan even as the president agreed to triple troop levels there. Obama’s top White House adviser on Afghanistan and his special envoy for the region are described as believing the strategy will not work.

According to the book, Obama said, “I have two years with the public on this” and pressed advisers for ways to avoid a big escalation in the Afghanistan war.

“I want an exit strategy,” he said at one meeting. Privately, he told Vice President Joe Biden to push his alternative strategy opposing a big troop buildup in meetings.

While Obama ultimately rejected the alternative plan, the book says, he set a withdrawal timetable because “I can’t lose the whole Democratic Party.”