I looked up the Reagan/Harley Davidson tariff. Long time ago and I'm sure the treaties have changed. It was signed by President Reagan, but on the recommendation of the International Trade Commission, which determined that Harley Davidson was harmed by Japanese competition coming from four firms. The reason appears to be economic damage to Harley from imports, no charges of dumping. I don't know if that's still enough. It's important to note these are reactions to specific violations. Harley had to prove their case. The article notes US auto manufacturers made the same claim and lost. And there is recourse in US and international courts after the decision. Reagan signed it, but the action was undertaken by Harley and won in the ITC first. Not exactly a Presidential prerogative.
There's probably room for actions like this relative to China. There should certainly be a Congressional moratorium on news trade deals until after the election, but where there are substantial existing agreements, thinking NAFTA, it's a long struggle.
Thanks very much for the information.
“The reason appears to be economic damage to Harley from imports, no charges of dumping.”
I don’t know what was in the documents. I do know that there was a metric crapload of dumping going on, subsidized by the Japanese government.
If Trump needs specific violations, he will be able to identify them.