President Hugo Chavez has nationalized the control of four oil fields and a refinery in Venezuela's Orinoco River Basin, affecting foreign companies like ExxonMobil, Chevron, ConocoPhillips, BP, France's Total and Norway's Statoil ASA.

The assets are worth $30 billion, with compensation by Venezuela to the companies yet to be worked out.

In taking the action last week, Mr. Chavez continued to carry out a policy that melds his own personal attitude toward the United States with a course he has set to free Venezuela as much as possible from external control. He includes in this category influence from foreign governments and companies, in particular the United States, and any future need on Venezuela's part to toe the line in dealing with international financial institutions. On Thursday, he said that he plans also to nationalize Venezuela's banks and a steel company.

He also announced that Venezuela would be withdrawing from both the World Bank and the International Monetary Fund. It has paid off its loans to both with revenue from the high oil prices of this decade.

Some of what Mr. Chavez is doing changes little for Venezuela. Its oil industry was under national control from 1975 to 1992, when privatization resumed. Greater national control of development of the country's oil resources could mean that investors will be less likely to provide the necessary funds to keep Venezuelan oil production up to date.

On the other hand, world market demand for oil -- largely depoliticized in nature -- is such that Venezuelan nationalization of its reserves will likely make almost no difference, in sales or investment. Three-quarters of the world's oil reserves are under state control in any case.

Mr. Chavez's actions are another step in a resurgence of socialism as the governing theology of economics in Venezuela, and potentially at least in some of the rest of Latin America. Looking around the world, it is probably fair to say that the economic philosophy of a government has little to do with actual oil production. An expansion across Latin America of Mr. Chavez's approach, however, would probably mean that more American companies would lose parts of their concessions and other positions in the region.

Mr. Chavez's own basic problem with the United States is political and goes back to 2002, when the administration of President Bush prematurely recognized an ultimately unsuccessful coup d'etat against Mr. Chavez. He is also no doubt aware that across the years some other Latin American leaders have come to premature, sticky ends for their opposition to the United States. He is noisy about this subject on the world stage to try to ensure himself against such U.S. action against him.

The state of U.S.-Venezuela relations is painful. It would be unfortunate if Mr. Chavez and his country became another Castro's Cuba stuck in America's craw as time goes by. It is hard for Washington to take steps toward Mr. Chavez while he lambasts the United States publicly. On the other hand, the United States is the big power and Venezuela the small one. Venezuela is also the fourth-largest foreign supplier of oil to the United States.

The importance of the relationship would seem to suggest greater efforts on the part of Mr. Bush and his administration to patch things up with Mr. Chavez and Venezuela.