The challenge in this period ahead is to consolidate the gains we have made and seal the extremists' defeat. We have learned through hard experience what happens when we pull our forces back too fast; the terrorists and extremists step in, they fill vacuums, establish safe havens, and use them to spread chaos and carnage. General Petraeus has warned that too fast a drawdown could result in such an unraveling with Al Qaida and insurgents and militia extremists regaining lost ground and increasing violence.