General Discussion

It said that the president couldn't use the law on which he based them (IEEPA) to impose tariffs.

There are other ways for the president to legally impose tariffs, at least on a temporary basis. He chose not to use those laws because the easiest to justify only allows the tariffs to be in place for 150 days before requiring congressional approval. He didn't want to risk congress rejecting the tariffs, so he took a legal gamble and lost.

So - first - all he has done since the decision is talk. Talk is not illegal. If he does impose tariffs under a different law, he isn't necessarily breaking the law by doing so. He isn't even defying Supreme Court.