Ronin, I understand your point.  I teach reading comp to honors students, and always remind them to not let their biases lead them to see things that aren't there.  I see it's possible to interpret "...what was happening with REGARD to the Civil War..." to mean things happening in Jackson's time which eventually built up to the Civil War, especially if said by someone who's not precise about his choice of words.  Trump may be a "concept" person who means what he said about Jackson being angry at the dumb goings-on, and wasn't focusing on the exact years things happened.

But I hope you also recognize that most people who care about both informing and being understood would say something like, "Jackson was angry with the unreasonable things going on IN HIS TIME that eventually led to the Civil War."  If you don't say it the "common" way, you leave yourself open to the grammar police, political opponents, and those who really believe you're uneducated.