Chairman of the Joint Chiefs of Staff Admiral Michael Mullen, 21 Jul 2010.

Admiral Mullen acknowledges that it may take years to fully defeat the Afghan insurgency. But he says that is not what the United States expects to accomplish by this time next year, when President Barack Obama has said he will begin to withdraw US troops. But Mullen says the year-and-a-half the president allowed for the new strategy to prove itself is adequate.

"Insurgencies last a long time," said Mullen. "But, as you look at how long it took to turn Iraq around, it was about 18 months. Now, we're about two-and-a-half years later, and we're still working in Iraq. But it was sort of that period of time where it really turned. Turning it doesn't end it, [but] you've got to turn it to get it moving in the right direction."

The admiral says the situation in Iraq seemed impossible to resolve a few years ago, and, while the two countries are very different, and progress in Iraq is not a guarantee of progress in Afghanistan, it does give him reason to be hopeful about Afghanistan - even during the current period of heavy violence and, at best, slow progress.

"There are similarities and differences between Iraq and Afghanistan, and I understand that," added Mullen. "But I don't accept the fact that, just because it takes insurgencies a long, long time [to be defeated], that we're not at a point where it can't be turned, because I think it can. It doesn't mean it's going to be easy. But, I think it can be [turned] over the period of time that we're talking about."