You are forgetting that other countries respond with tariffs of their own. Ultimately, the outcome balances out, just with higher prices for everyone. Local producers that rely on exports lose while those that sell locally win - as long as they don't rely on imports for raw materials.
Consumers lose, especially on stuff that will never be produced locally, or rules on raw materials that can't be sourced locally.
The PACs aren't the issue, it's that they are allowed unlimited spending. In Canada, where I live, third party spending is capped at $350K per registered partisan group.