I have problems with the so-called right/left projection in the Huffington Post article. I don't agree with the "conservatives," but I don't agree with the "liberal's" approach either.
The smart thing to do would be to discuss both sides in schools and even more. Afterall, the "right" and "left" as projected in that article both attempt to monopolize all issues and act as if only that "right" is the alternative to that "left" and vice versa. The children are short changed in either case.
Both Thomas Jefferson and John Calvin should be read and discussed. What is termed the Enlightenment should be discussed in terms of support and negative criticisms against it.
The Judeo-Christian, Deist, and other aspects of the Founding Fathers should be taught. The concept of "separation of church and state" should be taught, but the free exercise aspect should be given just as much emphasis as the no-establishment aspect. The historical, constitutional arguments should be covered. There are court cases where both majority and dissenting opinions should be taught.
"American exceptionalism" should be taught as a view that some, but not all, Americans hold. The so-called U.S. "free-enterprise system," should also be discussed in terms of pros and cons and whether or not there really is any such thing or whether it's a target put forth by certain theorists. The pros and cons as held by the various sides concerning regulation versus privatization, etc., should be taught.
Personally, I still use B.C. and A.D. because I have no idea what the so-called Common Era is supposed to signify greater than the birth of Jesus Christ. If there hadn't been a Jesus Christ, there wouldn't be a separation regardless. There would be a calendar with at least as many years as the Judaic, which right now stands at the year 5770.
As for the Bill of Rights, the Second Amendment does address the right to bear arms. Of course, it is within the context of there being a need at the time of passage for a well-regulated militia. The issues surrounding that should be taught.
I'm not sure exactly how to teach about hip-hop "as an example of a significant cultural movement." It is a music genre that's spread around the world. It appears to be as rock and roll and jazz and other genres that are certainly historical facts. Again, the pros and cons from the various perspectives should be taught. The public schools don't have to take positions for or against in general. Hip-hop has its dark side, of course. There have been gangster rappers who have called for killing police officers for instance. Such things (killing police officers) shouldn't be hidden or supported or condoned. Of course, revolutions should also be studied from all the various angles. Not all police officers everywhere are always on the side of real law-enforcement. There are rogue cops gone bad, so to speak. There is also the danger of the police state.