The Economist had a recent article on the strangely 19th century world of great power rivalry that Obama faces.
Whilst I'm broadly in accordance with the main policy recommendations it makes, here, as I see it, are the five most important foreign policy moves that Obama should make in his first term, in chronological order (but not necessarily in order of priority).
1) Afghanistan and Iraq. Obama should make Afghanistan his first foreign policy focus. Bluntly put, America needs to deploy far more troops to Afghanistan. Far more than any other conflict out there, America needs a clear victory in Afghanistan. If the conflict smolders on, there is a progressively greater risk of it prompting all out anarchy in Pakistan. This will require stretching an already overstretched American military still further. This can be helped by withdrawing some forces, cautiously, from Iraq. Obama should also use his massive political capital in getting more assistance from America's allies on the ground. America has to treat Pakistan with kid gloves. The administration there cannot survive full scale American attacks over the border. This will hamper America's efforts on the ground, but it will be the best option in the long run.
2) Reconciliate with Syria. This is absolutely vital to an Iran strategy. America needs to move Syria away from the pro-Iranian block. In effect, Syria gets the Golan Heights and a rapprochemente with America in exchange for severing links with Iran, Hamas, and Hizbullah and a permanent peace treaty with Israel. Obama should also make it clear to Syria that he intends to push any new Israeli Prime Minister to the negotiating table.
3) Defuse growing Russian militarism. America has too many other concerns for a second Cold War right now - it needs Russia on board, even if this involves a show of apparent weakness. American should make it clear that it will take Russia's interests seriously. This may require putting pressure on would be NATO members like Georgia and the Ukraine to cool the rhetoric, a postponement of America's missile defence shield in Europe, and a willingness to negotiate with Russia on Arctic Oil. With these two big carrots, plus a willingness to work with Russia to ameliorate the world financial crisis, America should be able to get Russia on board for negotiations with Iran, a deepening of their assistance in Afghanistan, and their assistance with international terrorism. Eastern Europe will be pissed off, but they have nowhere else to turn. Despite this, America should reiterate its commitment to democracy and warn Russia that any country that is ready for NATO membership and which is truly in favour of it will eventually get to join the club. However, America should reassure Russia that it will move slowly and be ready to address Russian concerns at every stage.
4) Do not allow Iran to develop nuclear weapons. This has to be Obama's big priority. A nuclear Iran would be the biggest threat to world peace and stability out there. As long as Iran can play divide and rule, a negotiated peace has no chance of success. This is why America needs Russia, China, and Syria on board. Very large carrots and very large sticks will need to be produced if this is to succeed, and Iran needs to be made clear that it will ultimately stand alone if it proves intractable. Iran could be reassured by an American deal with Syria, a drawdown in Iraq, and an administration determined to push for Palestinian statehood. Iranian presidential elections are next year, and anything America can do to encourage Iran to vote for a moderate will pay rich dividends. Iran's interests also coincide with America's in Afghanistan and Pakistan - Iran hates the Taliban, and is nervous at the prospect of instability in Pakistan.
5) If America can prevent the nuclearisation of Iran, achievement rapprochement with Russia, Syria, and Iran, and successfully close the conflicts in Iraq and Afghanistan, then I will be surprised and delighted. Resolution of all of these things is necessary for the challenges that America will be facing ten years from now. In particular, I see Pakistan as likely to be a long term problem. American and Russia will clash over Arctic oil, but if this occurs in the context of a warm and successful relationship, it has a greater likelihood of success. With Iran and Syria no longer acting as agents of chaos in the Middle East, the Israeli-Palestinian problem will have a greater likelihood of success. The biggest long term threat to world peace and stability will inevitably be the rise of China as America's equal in world affairs.
Therefore, Obama's final move should be to seek to begin the process of reordering international institutions according to a more multipolar model. It should do this now, whilst its international credit is still strong. If it waits another 10 years, when the BRIC group of countries will be in an even stronger position, then its hand will be much weaker. Thus the fifth priority of an Obama presidency should be to start putting out feelers for a recasting of the UN, the IMF, the World Bank, and the WTO, to more evenly distribute power whilst ensuring that America still has a strong voice. This will be a long and time-consuming process that will make plenty of work for everyone in the diplomatic establishment. The sooner America starts, the better.