The writer is chief economist of the International Center for Law & Economics and writes the Economic Forces blog

Donald Trump has promised a renewed push for tariffs when he returns to the White House. The stated goal is to protect American manufacturing jobs, but some approaches would achieve this far more effectively than others.

The historical record shows that, while tariffs can preserve specific manufacturing jobs in the short term, poorly designed trade barriers destroy more American factory jobs than they save. Understanding these trade-offs is crucial for policymakers determined to use tariffs. Trump has said he will impose tariffs of 25 per cent on all imports from Canada and Mexico, and an extra 10 per cent on Chinese goods. But implementation will be key.