It's no secret that Vladimir Putin wants modern day Russia to be larger -- much like the Soviet Union.
But the Russian president's imperialistic flair may be driven more by economics than political ambition.
At least that's the theory put forth by billionaire investor Jeffrey Gundlach, who says that Putin's efforts to reclaim Russian-speaking territories are fueled by a looming demographic disaster.
Russia is aging rapidly. Its working-age population is on track to shrink by 14% over the next 35 years, posing a real risk to economic growth.
"Russia will have the largest implosion of population in the history of the world," Gundlach said last week at ETF.com's Fixed Income Conference. The legendary investor said that's excluding war, famine or disease.
"No wonder Mr. Putin wants to take over other nations that are Russian-centric. He needs people," he said.
In recent years Putin has brought Crimea back under Russian control and has sought to prevent Ukraine from joining NATO. There are concerns that he will try to reassert power over other Russian-speaking territories in countries like Estonia and Latvia too.
Gundlach, who is the founder of elite fixed-income firm DoubleLine Capital, pointed to Russia's elevated mortality rates and a very low fertility rate.
Even the World Bank is worried about these issues. It recently urged Russia to try to reduce the impact of aging by encouraging individuals to save more, raising the country's relatively low retirement age and cutting down on bad habits like smoking and excessive drinking.
"Without adequate adjustments of policies and behaviors, an aging population could impair national growth and fiscal sustainability," the World Bank said in a report that pointed out Russia's population of those over 60 more than doubled to 18% in 2010 from 7.7% in 1950.