Military advisers react to Obama's Afghan plan

WASHINGTON - One day after President Obama spelled out his exit strategy for Afghanistan, his top generals went before Congress.

CBS News national security correspondent David Martin reports while they stand behind the president, they made it clear, the decision on troop withdrawals was his, not theirs.

Both General David Petraeus, the commander in Afghanistan, and Joint Chiefs Chairman Admiral Mike Mullen, the president's principal military adviser, said today they initially balked at President Obama's drawdown plan as too risky.

"The president's decisions are more aggressive and incur more risk that I was originally prepared to accept," Admiral Mullen said.

Petraeus said, "the ultimate decision was a more aggressive formulation, if you will, in terms of the timeline than what we had recommended."

They wanted to pull out fewer than 5,000 troops this year. But they were up against an option presented by President Obama's civilian advisers to pull out the entire 33,000 surge force by the end of this year. The president decided to pull out 10,000 this year, all 33,000 by September 2012.

"Is it going to be hard," Mullen said. "You bet it's going to be hard."

But Mullen said it would be even harder on the Taliban.

"The Taliban had a really bad year last year," Mullen said. "They're having a really bad year this year. They're going to have another really bad year next year."

Both men seemed to acknowledge their military advice was not politically realistic.

"More force for more time is without doubt the safer course," Mullen said. "But that does not necessarily make it the best course."

Petraeus said he supports the president's decision and will carry it out, but he refused to say he is comfortable with it.