Whoever is the next President of the United States, he or she will inherit a nation positioned in a world radically different from the world of 2000 or even 2001. I'm not merely referring to the threats we now face from radical Islam and Iran, or the nexus of Iran and Latin America, though these are parts of it. I mean that the world of 2009 and beyond will be one in which the United States sees its ability to influence events diminish (comparatively), because of two particular challenges that will probably endure for the next generation.
Our first challenge will be to manage the rise of new world powers. We have spent much of our political capital and international prestige on the Iraq War, and I say this as a supporter of the war. Other nations have not. Nations like India, China, Russia, and world regions like the European Union and south-east Asia have devoted their energy to economic development, largely untouched by the burdens of war. The effect is that as our relative power has remained static or decreased, the economic power (and to a lesser extent military power) of other nations has increased. The 21st century may come to look like the end of the 19th century where multiple countries have comparative advantages over one another, and increasing globalization raises less-significant countries in world events to preeminence. (Note: that was America back then!)
The other challenge will be to regain America's prestige in the world and in the Middle East especially. A recent poll of several countries in the Middle East dramatically illustrates our problem . In the region where our strategic interests are most tightly bound, America is distrusted, despised, and misunderstood. One glimmer of hope in the poll is that our values are not the source of the Arab world's ill-will-but our policies are. The way our next President interprets this kind of data will have decisive ramifications for our foreign policy. "Democracy promotion" has a sour taste in the Arab world's mouth because they perceive that it means "war for regime change."
If America can leverage good-will in Iraq from exertions of "soft power" (by building and defending Iraqi civil society), we will have struck the mightiest blow possible against al-Qaeda and radical Islam. In that case, look to see eventual turnaround of public opinion in our favor.