Gates went on to say:
The question, [Gates] said, comes down to "How do we signal resolve, and at the same time, signal to the Afghans and the American people that this is not open-ended?"
If President Obama and his team are waiting until they come up with an answer to that dilemma, it is no longer a mystery why the review is taking so long. Sorry, you can't commit to both the long road and the exit ramp at the same time -- you have to pick one or the other.
The very fact that the administration is still trying to figure out an elegant solution to this insoluble dilemma sends a strong signal, a signal that explains and motivates the behavior of various actors in ways unpleasant to the administration. Examples include:
1. Pakistan hedging its bets by continuing to protect the Afghan Taliban,
2. Providing the Afghan Taliban with an excellent recruiting and motivational tool, and guidance on how to adjust the tempo of their operations,
3. President Hamid Karzai hedging his bets by cutting side deals with Afghanistan's power players,
4. Local Afghans accepting U.S. assistance but also hedging by not resisting the Taliban (as reported by Bing West in his trip report),
5. U.S. conventional combat units doing their own form of hedging by getting passive and increasingly just going through the motions (also reported by West),
6. Anonymous leakers inside the administration attempting to preemptively cripple policy options they don't like.
When Gates said, "signal to the Afghans and the American people that this is not open-ended," I assume the Afghans he had in mind were Karzai, other top officials in the Afghan government, and officers in the army and police. He apparently wants to motivate those particular Afghans to make a better effort defending their country.
I doubt he was referring to the Taliban and the broad civilian population. They too are Afghans and have very likely received the message that "this is not open-ended."