A new age of abundant and cheap energy supplies is redrawing the world's geopolitical landscape, weakening and potentially threatening the legitimacy of some governments while enhancing the power of others.

Some changes already are evident. Surging U.S. oil production enabled America and its allies to impose tough sanctions on Iran without having to worry much about the loss of imports from the Middle Eastern nation. Russia, meanwhile, faces what President Vladimir Putin called a possibly "catastrophic" slump in prices for its oil as its economy is battered by U.S. and European sanctions over its role in Ukraine.

"A new era of lower prices is being ushered in" by the U.S. shale oil and gas revolution, Ed Morse, global head of commodities research for Citigroup Inc. in New York, said in an email. "Undoubtedly some of the geopolitical changes will be momentous."