The fact that Obama is taking flack from both the Left and the Right indicates that his policy on Afghanistan is probably about right. The Democrats are complaining that he is the tool of the generals. If he were a Republican, I would worry more about this argument, but I believe that Obama's natural tendency would be to not to go with the generals' recommendations. That means that they must have some good arguments and that they will have to produce results or he will turn against them. Furthermore, I have more confidence in Bob Gates and Hillary Clinton than in most politicians or bureaucrats and am encouraged that they are on board.
I am not personally convinced that we currently need to be fighting in Afghanistan. I think that Bush, Cheney, and Rumsfeld gave the Afghan war short shrift. They didn't really care about it; they cared about Iraq. The troops who died there were not appreciated, starting with Pat Tillman. Bush, Cheney and company were cowards; they were draft dodgers during the Vietnam War, and they hid during the 9/11 attacks. They felt they had to do something in response to 9/11; so, they sent troops to Afghanistan, but their heart was not really in the war, which is why all the troops, equipment and money went to Iraq.
Now that Obama is in office, Afghanistan if getting the attention it deserves for the first time. It deserves attention because Americans are dying there and we are spending billions there. Basically, I think Obama is saying to the military, "Okay, you've been in Afghanistan for eight years, but you've never had the manpower and resources to do the job. And you've never really been told was your mission was. Now, we are going to give you the men and resources to carry out a limited mission. You have 18 months. At the end of that time, if you've succeeded, or if it looks like success is impossible, we'll pull out. If something unexpected happens, we'll reevaluate then." So, the military has a chance to prove itself, after being given just the back of Bush's hand for eight years. We owe it to those who have died over the last eight years, and perhaps to the 3,000 who died on 9/11.