foreign countries ... even engage in a tactic known as “product dumping” — where foreign competitors will dump huge quantities of underpriced goods into U.S. markets for the sole purpose of driving American factories out of business.
In fact, as the anti-dumping law stands now, anti-dumping tariffs can be imposed in situations where even small quantities of imported goods are sold at prices that are slightly lower than those in other countries. Also, the purpose of the pricing is not taken into account.
So if Trump wants to reform our anti-dumping system to only address situations where there are "huge quantities" sold for the "sole purpose" of putting U.S. factories out of business, that would seriously constrain the anti-dumping law, and would actually be a huge improvement!
But of course, his writings on this topic are just his usual rhetoric, and that's not what he wants at all. From the rest of the op-ed (and all of his other trade rhetoric), it is clear that what he really wants is more restrictions on trade. And as much as I'd like to hold him to his word on anti-dumping, doing so on just about any other issue is scary to think about, so probably best to let this one go.