We really enjoyed the Uncle Eric's books from Bluestocking Press. They have some that would go along with a Government course. Political parties, etc. Much more entertaining reading than Notgrass, but also extremely informative! Maybe you could condense or skip parts of Notgrass and replace them with something more interesting?
Also, a field trip to your state capital is a great addition and could also replace some of the dry reading if you follow up with a written assignment or evaluation of the trip. Or even a local alderman's meeting.
"Ree-bee," Mom to United States Marine ds 21 * artist dd 19 * motion-loving ds 16 * piano-playing ds 11
"For Miss Minnie loved children and she loved books, and she taught merely by introducing the one to the other." from "A Consent," by Wendell Berry