Sherman Antitrust Act - precedent for scope creep

I don't expect much out of an editorial by Tim Griffin on the NDAA in the Daily Caller. And Griffin was as big of an apologist shit as I would have expected given his history. However, the Daily Caller has angry paleocons, civil libertarians, Ron Paul libertarians or whatever labels they want to use for themselves, in its commenters. So that's a little heartening. Some of us want to call a harmful law what it is, no matter if it comes with a (D) or an (R) next to its name.

In response to Griffin's downplaying of the danger that vague legislation will be applied in a new context later on, commenter Stewart Dawson said this:

Here's the problem. The Sherman anti-trust act. Anti-monopoly legislation warped to apply toward union busting ... Congress has a long and storied history about using vague phrasing to warp meanings to apply to whatever they want.

I am interested in learning more about Stewart's example. I'll put it on my copious reading list. By staying on top of the fact that there are real precedents of scope creep in U.S. history, this is how you have some substantiation for saying that it can happen again in spite of the possible good intentions of the non-disingenuous ones who want to use the new detention powers just on true positives intent on mass murder.