The United States, the most powerful nation the world has ever seen, will be getting a run for its money from China in the decades to come. According to a report by Albert Keidel of the Carnegie Endowment for International Peace, China's economy will surpass the U.S. by 2035 and will be twice its size by the middle of the century.

The thought of the U.S. not being number one is mind blowing, but not surprising. China's growth rate during this decade has averaged more than 10% and is still going strong even amid a global economic slowdown. Meanwhile, Chinese exports to the U.S. exceeded imports by about $75 billion between January and April. Chinese exports probably were not slowed much by the recent devastating earthquake that killed more than 69,000 probably did little to slow China's economy.

Not surprisingly, talk of protectionism seems to be on the rise in the U.S. One foolish member of Congress has proposed slapping new tariffs on Chinese goods to punish the country for currency manipulation. Such a law would probably be struck down by the World Trade Organization. Barack Obama, the presumptive Democratic presidential nominee, pledges to fight for a "a trade policy that opens up foreign markets to support good American jobs." He also wants to "amend" the North American Free Trade Agreement. Republican John McCain takes the opposite approach, vowing during his recent overseas trips to continue President Bush's free trade agenda.

Possibly more than ever before, smart stock investing requires a clear and wide forward view. If you don't have an undeniable road map for where your chosen companies are headed, you must dig deeper and you need to do it right now. Specifically, if the companies that you have chosen to invest in don't have a declared international focus, you must be certain of why that is and if it's appropriate.

Barring some unforeseen worldwide economic crash, which is in fact extremely possible, the fact sheet on investing these days is headed with the word global. If your portfolio is not thoroughly salted with companies that do business on a worldwide scale, then your portfolio is scheduled to wither and wane over the next three to five years. Global diversity is essential right now, and will continue to be a requirement from here on out.

It's my opinion that one of the most important criteria these days for successful portfolio building is to create a portfolio footprint that covers at least three different countries. If you have the funds to spread out and you're a fan of diversity, just for safety I suggest that you base your portfolio across five to seven countries. I would suggest the following research focuses as a sample to get your global thinking started.

Consider China for heavy manufacturing, machinery, electronics manufacturing, and a range of consumer goods. I'd be shy of putting any money over there at the moment, however, because to me their stock market is currently overinflated in value.