The high hopes surrounding Barack Obama's presidency are mostly a good thing, as they remind us that much of the anti-American sentiment that is so apparent around the world is not and need not be permanent.

But this anticipation is also a problem for Obama, as it will be difficult – and in some instances impossible – for him to meet expectations. There will be no Palestinian state this spring; nor will there be a global climate change pact or a new trade accord or an end to poverty or genocide or disease anytime soon.

The reasons go beyond the reality that big accomplishments require time and effort. The new president faces extraordinary constraints – constraints that will make it essential for other countries to do more if stability and prosperity are to be the norm rather than the exception.

The most obvious limitation stems from the state of the US economy. Two million jobs disappeared in the last four months alone. The housing market continues to deteriorate. The Untied States' GDP is contracting at an almost unprecedented rate.

As a result, Obama will have no choice but to devote the lion's share of his time and attention to reviving the economy. More than anything else, his success in this domain will determine the perception of his administration. Even he acknowledges that this will require him to delay fulfilling several other campaign promises.

A second constraint stems from all the crises that will greet the new president. Israelis and Palestinians just ended a low-level war. The situation in Iraq is improving but is by no means assured.

A third constraint stems from trends in the international system. The era of US unipolarity is over. Obama will inherit a world in which power in all of its forms – military, economic, diplomatic, and cultural – is more widely distributed than ever before. This means that he will have to deal with a large number of threats, vulnerabilities, and independent actors who may resist bending to the US' will.

All of this will make it more difficult for the US to get things done in the world – and for Obama to have any chance of meeting the expectations being set for him – without the active assistance of others. And since Obama will want to meet some of those expectations, other countries had better be prepared for American requests – and pressure – that they act with the US rather than act against it or sit on their hands.

European countries should be prepared for US calls to do more to meet the increasing security challenge in Afghanistan. At stake is the relevance of NATO in a world in which the principal security challenges facing Europe are to be found outside the NATO treaty area.

Countries of every sort will face requests to do their part to overcome hurdles to a new global trade accord. Tariff and non-tariff barriers will need to come down. Rich countries will be asked to reduce subsidies; poor countries to open up their markets.

Arab leaders that criticize the US for the perceived shortcomings of its policies toward the Middle East will be asked in turn how much more they are prepared to do to bolster the government in Iraq. Once the fighting between Israel and Hamas subsides, the question of what the Arab states will do to strengthen Palestinian moderates and to make peace with Israel is sure to arise.

This list is a long one, but it could easily be much longer. The rest of the world was often unhappy with George W. Bush, for both the content and style of his foreign policy.

Now others will find that the alternative to the US going it alone or withdrawing from the global scene is real multilateralism, which requires their willingness and ability to commit resources to deal with pressing challenges. Obama is likely to be more diplomatic than his predecessor, but he is also likely to be more demanding.

The author, Richard N. Haass, is president of the Council on Foreign Relations Project Syndicate.

(China Daily January 22, 2009)