OK, I have kept pretty quiet on the US elections so far, but now I think I have a question that I can answer and explain without riling anyone up. Given the question is specifically about an INTERNATIONAL perspective based on the candidates REMAINING in the race, I am going to stick my neck out and say...
Clinton.
For these reasons... basically, I don't think Obama has enough nous or experience YET when it comes to dealing with international issues. For starters, with 1 million + deaths in Iraq and Afghanistan linked DIRECTLY to the foreign policy of the current administration, the world needs a US president who is somewhat sympathetic to the UN - because the flood of people from Iraq to neighboring countries, the destabilisation of Pakistan, the igniting of sectarian violence in Iraq, the uncertainty in the oil markets and everything else that has flowed from those conflicts are having international effects and therefore require an international solution. Given that a Hillary presidency will by default have the input of Bill, then I think that for at least one term she is the best option in terms of bringing the UN on board. The trouble with having a president without international nous is that you end up with what we have had for 8 years - a president lacking an understanding of the complexities of the world institutions meaning that the principal advisors end up running the show and furnishing their own fiefdoms (Cheney) and prejudices (Rumsfeld) and so forth.
Now don't get me wrong, I am sure that Obama as a person is probably a better bet than Clinton. But right now, I don't think he is ready for the messy reality of foreign policy. I know that when it comes to presidents, the US voters tend to vote on domestic issues and this time will be no different given the economic situation at home, and it is going to be a long time before the average US voter accepts that their nation is slowly but surely going to be overtaken by China, and realise that some of the domestic 'issues' (faith, abortion, whether a woman or a black man should be president) have pretty much been resolved in most other developed countries.
But looking at it from an international perspective, I think President Clinton and Vice President Obama would be ideal. Then he can get himself some more practical experience and run for presidency when he has a firmer foundation.
Note: I am not suggesting that Obama has a weak knowledge or understanding of the world - his speeches on Sudan and HIV in Africa make that clear, but rather he needs some more experience dealing with the relevant institutions. But he will certainly make a fantastic president one day.
Obama '16?