The U.S. government has extended the comments period in a national security probe into imports of components for power transmission transformers. That may indicate a lack of interest in the case from the industry. Nonetheless, the Trump administration has started to extensively use national security reviews as part of trade policy and so will likely pursue it. Imports of the transformer cores that are the focus of the case come mostly from Canada and Mexico, having accounted for 50.6% and 46.3% of shipments in the 12 months to April 30. While neighbors and collaborators in the USMCA t...