In an interview published today by Time Magazine, President Barack Obama spoke about some of the obstacles he's faced in his efforts to pursue peace for Israel:

I'll be honest with you. A: This is just really hard. Even for a guy like George Mitchell who helped bring about the peace in Northern Ireland. This is as intractable a problem as you get. B: Both sides--I think the Israelis and Palestinians--have found that the political environment, the nature of their coalitions, or the divisions within their societies were such that it was very hard for them to start engaging in a meaningful conversation. And I think that we overestimated our ability to persuade them to do so when their politics ran contrary to that.

From Abbas' perspective, he's got Hamas looking over his shoulder and I think an environment generally within the Arab world that feels impatient with any process.

And on the Israeli front, although the Israelis I think after a lot of time showed a willingness to make some modifications in their policies, still found it very hard to move with any bold gestures.  And so what we're going to have to do--I think it is absolutely true that what we did this year didn't produce the kind of breakthrough that we wanted and if we had anticipated some of these political problems on both sides earlier, we might not have raised expectations as high.

Moving forward, though, we are going to continue to work with both parties to recognize what I think is ultimately their deep-seated interest in a two-state solution in which Israel is secure and Palestinians have sovereignty and can start focusing on developing their economy and improving the lives of their children and grandchildren.

(emphasis added)