Of course there are few members of AL Qaeda left in Afghanistan. Most of the insurgency is comprised of Taliban and some disgruntled warlords. The Taliban have never really threatened the US and if the US withdrew they are not likely to welcome AL Qaeda back into Afghanistan. If the Taliban gain power or share power they do not want to provoke another invasion with regime change. The idea that the US has not sought to meddle in Afghan affairs is truly ludicrous. From the invasion to the installation of Karzai to now the US has continually tried to shape Afghan affairs and expand its influence. The idea that an occupying country along with NATO is not trying to interfere in Afghan affairs is just plain goofy.
Mr Obama said America had not chosen the war, and had not sought to meddle in Afghan affairs or expand its influence.
It had, he said, been "attacked viciously on 9/11", and al-Qaeda leaders and their Taliban allies were still in the region and had to be defeated.
The US aimed to deny al-Qaeda a safe haven and reverse the Taliban's momentum, he said.
He promised troops that they were being "backed up by a clear mission and the right strategy" and that they would have "the support to get the job done".
"I'm confident all of you here are going to get the job done in Afghanistan," he said to applause and cheers.