LAST year I endorsed President Obama for re-election largely because of his commitment to putting science and public health before politics. But now the Obama administration appears to be on the verge of bowing to pressure from a powerful special-interest group, the tobacco industry, in a move that would be a colossal public health mistake and potentially contribute to the deaths of tens of millions of people around the world.

Although the president’s signature domestic issue has been health-care reform, his legacy on public health will be severely tarnished — at a terrible cost to the poor in the developing world — unless his administration reverses course on this issue.

Today in Bandar Seri Begawan, Brunei, representatives from the United States and 11 other nations begin the latest round of negotiations over the Trans-Pacific Partnership, a multinational trade agreement. The pact is intended to lower tariffs and other barriers to commerce, a vitally important economic goal. But if it is achieved at the expense of people’s health, the United States and countries around the world will be worse off for it.

The early drafts of the agreement included a “safe harbor” provision protecting nations that have adopted regulations on tobacco — like package warnings and advertising and marketing restrictions — because of “the unique status of tobacco products from a health and regulatory perspective.” This provision would have prevented the tobacco industry from interfering with governments’ sovereign right to protect public health through tobacco control laws.