There are published charts one can find online that detail the various state's and Canadian Province's laws regarding brakes on trailers. They can vary significantly. Most of these entities consider a vehicle (car, truck, SUV) attached to, and towed behind, another vehicle as a "trailer". So depending on the weight of the towed vehicle and the rules of your specific jurisdiction, supplemental brakes may or may not be required. Given the expected weight of a Wrangler, in most states you would be required to utilize supplemental brakes.
I have been towing behind my motorhome(s) for years and would not do so without supplemental brakes. I can tell you from experience they help greatly, especially in hilly areas. And while I am not an attorney, I suspect if one ever gets sued because of a crash and you do not have supplemental brakes your defense may be compromised as a result, regardless of where you are. Just a wary suspicion on my part in today's litigious society.