Political, demographic and diplomatic changes in the U.S. during the past decades suggest the country will probably continue to be polarized into Democrat and Republican extremes, and the superpower will probably continue to rely on immigrants for economic growth and will likely play the global policeman role to a lesser extent, five academic researchers said at a symposium in Tokyo.

The five, from different academic backgrounds, each explained the trends in the U.S. in the past decades and tried to predict the future while pointing out some uncertainties, such as the global economy, and changes in the political situations in Asia, the Middle East and other parts of the world.

The five scholars were guest speakers at the symposium, titled "Destination of the U.S.; predicting what the U.S. shapes up to be in 10 years," organized by the Keizai Koho Center on Nov. 1.