U.S. President Donald Trump has approved a “ partnership” between Nippon Steel and U.S. Steel, green-lighting one of the most geopolitically consequential foreign investment deals of the year.

Trump said on Sunday that the United States would control U.S. Steel, though the specifics — including whether the transaction would amount to a Nippon Steel minority stake or joint venture — are not yet public. Yet the approval is not just welcome news for the steel industry in the United States, but injects new confidence into U.S.-Japan economic security cooperation at a delicate time.

The move is a sharp departure from Trump’s earlier, politically motivated stance opposing foreign ownership of U.S. Steel and reflects his administration’s responsiveness to a restructured, supercharged investment pitch from Nippon Steel: $14 billion pledged for U.S. operations, including up to $4 billion for a new steel mill and $1 billion for greenfield development.