Free global markets opened doors for Hugo Chavez and Vladimir Putin, who are now slamming them shut.

In reasserting state control over their economies, the leaders of Venezuela and Russia are bucking the very capital flows and expanded markets that buoyed their oil-producing nations in the first place by delivering record energy prices and the strongest global growth in a generation.

“These countries actually benefit from globalization, yet are now turning their backs on it,” a senior economic adviser to UBS AG in London, George Magnus, said. “It all smacks of a shift in power that comes with money.”

The two leaders, whose economies benefited from a tripling of oil prices since 2002, aren’t alone in thumbing their noses at globalization. Thailand’s military government last week placed new restrictions on foreign ownership of companies. The president of Ecuador, Rafael Correa, said he may default on the country’s foreign debt. Bolivian President Evo Morales is forcing energy companies Petrobras SA of Brazil and Repsol-YPF SA of Spain to give up majority control of assets.

While nationalistic politicians and resource-rich economies may be enjoying the moment, biting the hand that feeds them will lead to less foreign investment and weaker growth, economists say.

“It’s a false hope that they can take these actions and not cause some damage,” a former U.S. Treasury undersecretary for international affairs now at Stanford University in California, John Taylor, said.

Mr. Chavez, 52, is trying to remake Venezuela along socialist lines following his election last month to a second six-year term. In a January 8 speech, he pledged to nationalize the country’s utilities and strengthen the state’s hold on heavy-oil joint ventures that involve international oil companies including Exxon Mobil Corp., BP Plc, and Total SA.

Mr. Putin, meanwhile, is tightening his grip on Russia’s energy industry by buying stakes from foreign companies after threatening to revoke licenses, having already forced the bankruptcy of OAO Yukos Oil Co. and the eventual sale of most of its assets to friendly hands.

Open markets benefit oil producers as development in China and India, and the fastest global growth since the 1970s, increase energy demand. Oil prices reached a record $78.40 a barrel last July and world daily demand for crude will rise 1.7% to 85.9 million barrels this year, after gaining 1.1% in 2006, the International Energy Agency in Paris said.

Venezuela’s oil revenue added $50 billion to government coffers last year, according to the adjunct fellow for Latin American studies at the Council on Foreign Relations in New York, Shannon O’Neil. That financed about half of the country’s budget, allowing Chavez to fund domestic subsidies and overseas aid to propagate his “21st-century socialism.”

“It’s global capitalism that’s funding the socialist turn in Venezuela,” Ms. O’Neil said.

Russia’s energy exports finance about 30% of the government’s budget and have transformed a country that partially defaulted on its foreign debt in 1998 into a creditor nation, according to an economist at Dresdner Kleinwort in London, Ivailo Vesselinov. Russia’s foreign-currency reserves have expanded six-fold in four years, to $303 billion.

“Oil’s most striking impact has been on Russia’s fiscal accounts,” Mr. Vesselinov said. “That’s a major turnaround.”