HUMINT: Estimate the Future
The United States is not an empire and never has been. CEOs behave like micro empires but are primarily contained within their industries. Free trade is a construct that facilitates the redistribution of wealth in ways that socialism could never do and the criteria to do business with America's industrial empires is low - but that is hardly facilitated by the United States Government through militancy. If it were, the factories that make American Industry's competitors products would be flattened by JDAMs. By supporting the rule of law, freedom of speech, religion and press - the United States is anti Empire. Consider the definition of empire and how unlike the United States it is.
I don't see China taking the U.S.'s role as super power because of who we are and who the Chinese are. If one compares size alone they are missing the most important trend driving globalization - culture! Diversity is the core component that makes globalization possible and China doesn't have it. It never will. The Chinese do well as sub-cultures inside other cultures but they do not integrate well. Their industries are mostly copy-paste version of American models and they do it for less. If anyone nation were able to take the gauntlet away from the U.S. it would be India. With Baliwood, they are copy and pasting as much of our culture as they can and doing almost everything we can do, for less. Right now, they are doing Seinfeld impressions and our kids are doing Harold and Kumar impressions. Pop culture drives the trends driving globalization. Crouching Tiger, Hidden Dragon... Nope, no room for product placement there.
The purpose of world government is only to facilitate international trade. Inviting nation states to the table that do not subscribe to the rule of law makes world government an impossibility. Any World Government body would have to establish constitutional criteria for each existing nation to be considered a nation by the body. Doing so would destroy the concept of national sovereignty. The national identity would also come under question because relativism couldn't interfere with World Government policy and remain functional. For example, look at the IAEA. Mohamed Elberadi is perplexed that he has to protect Iran's nuclear reactor deals with Russia from a concerned U.S. and Israel - while his behavior is highly predictable, I don't call it World Governance.
To some extent it is already happening but no system is benefiting more from interpersonal interaction online than sitting governments. Beyond commerce, the internet serves as a means to track political and economic sentiment. Such measurements can go almost directly into policy formulation thereby creating a sense in the public sphere that the government is always one step ahead of the concerns of its citizens. The Internet is also a means to organize but is also subject to supervision. The supervision, benign or not, facilitates the prosecution of certain policies. In Iran for example, bloggers are regularly imprisoned for blogging. The Internet is developing a sense of freedom among Iranians but poses no significant threat to the Iranian government as long as the government is able to filter content. In terms of information liberty and information empowerment, the internet is only limited in terms of access. In the new world of Technocracy there are only two breeds of human being - online and off line. The off line individual will miss out on the ability to participate in Technocracy but the majority of those online will only opt to participate in ephemeral commitments such as porn and joke email. The freedom to choose content affords the user the ability to isolate themselves instead of explore. Presumably both types of behavior will occur. It would be interesting to see how internet usage evolves for those individuals not fixated on entertainment. It may be that trivial entertainment and some higher pursuits merge as has occurred with - "human computing" - see Google video tech series.
WHAT WILL HAPPEN NEXT - My Guesses
India and Europe, the two cultures diverse enough to capture the world's imagination and attention away from the United States, are both bogged down by socialism, language barriers and poverty. Both are lacking room to grow. The best and brightest from those societies will continue to move to the United States. To balance the quality of life they'll send money they make in the United States back home. In places that have room but do not share American cultural traits I see a need for new developments like those popping up around Las Vegas. To accommodate a growing, internet using, middle class - I think community developments are going to start springing up in places we wouldn't have anticipated before. The foreign policy of the United States will continue to transition away from containment to empowerment. Containment is the antithesis to globalization. A great number of societies may commit suicide in the process but isolation isn't an option any longer. The pace of growth around the world is such that the US will serve itself by creating copies of American community infrastructure in corners of the world accepting to the idea. Mexico might be a good place to start in order to stem the tide of immigration from that country.