> Have to agree. What does Obama have to lose by just going out on a limb and ending a horribly failed policy?

Because "like so many others" he simply doesn't have the power to; it requires Congressional approval. I suppose he could do what you want and unilaterally declare it over, but that would be a very clear breach of power and would result in many moderates and liberals decrying his overreach. It would end up - at the least - the subject of legal action and an injunction and perhaps even spur bipartisan support for impeachment proceedings.

The power of the Presidency is in general greatly exaggerated by the media. The President has broad power to set the agenda (which the rest of the government and the country is largely free to ignore) and has some power over policy/legal execution (particularly within foreign affairs), and over the military, but that's about it. Even within the executive branch the President is not as all-powerful as the media or even high schools tend to imply: even excluding agencies that are altogether independent, the President generally cannot walk in and tell people what to do.