The Feb. 9 article “GOP statesmen propose replacing Obama climate policies with carbon tax” failed to remind readers of a compelling reason — highly relevant to the current debate over tax reform — that a carbon tax is the most workable approach to addressing carbon emissions. Any regime we adopt must have a means to impose our “carbon price” on imports. If not, we can expect major producers of climate gases (e.g., steel furnaces) to be replaced by plants in low-carbon-cost countries (long known as “leakage”).