timatkn: "A passport is not required for an RABC but it is the easiest. You can use your drivers license and social security card instead as an example BUT to re-enter the US government requires a valid passport. *edit* you can also re enter with a passport card or real/enhanced ID.
T"
You do not need a passport for the RABC or admission to Canada. However a passport, a passport card or an enhanced driver's license to get back into the US. A real id driver's license will not do the trick. An Enhanced Driver's license is only available in a limited number of states (Michigan, Minnesota, New York, Vermont and Washington) and requires the same level of documentation as a passport.