Trump Tariffs Aimed at Reviving Manufacturing Are Doing Opposite

President Donald Trump’s signature trade policy is threatening to backfire by upending other top priorities: the revival of US manufacturing and the American Rust Belt.

In Illinois, Trump’s tariffs prompted a compressor maker to delay a key equipment purchase after an ambitious factory revamp. Rockwell Automation Inc., a Wisconsin-based producer of factory tools, says some manufacturers are putting projects on hold because of uncertainty over costs and future demand. Snap-on Inc. is seeing similar hesitancy among car mechanics.

The warnings underscore the rising worry that turbulence from Trump’s trade wars will smother the progress US manufacturers have already ...