That is what I carry with me when shooting, along with "We The People", a thin book containing many important U.S. documents and speech transcriptions, including, of course, the Constitution and Bill of Rights. You should also know key appeals decisions. It won't stop determined idiots, but has helped a lot on several occasions. I personally need to brush up on this, as the ones I know all relate to the press performing their jobs, and not to the average Joe on the street (though there is no real legal distinction between the two unless on private property).
Also, know the state laws that apply. For instance, I know CA penal code section 409.5 article (d) by heart, and carry the entirety of section 409.5 printed out and laminated. This will help you if you are working for the news media and want to go behind police lines. Article (d) is the response to police who state something similar to that which is contained in articles (a) and (b).
"California Penal Code Section 409.5
409.5. (a) Whenever a menace to the public health or safety is created by a calamity such as flood, storm, fire, earthquake, explosion, accident, or other disaster, officers of the California Highway Patrol, California State Police Division, police departments, marshal's office or sheriff's office, any officer or employee of the Department of Forestry and Fire Protection designated a peace officer by subdivision (h) of Section 830.2, any officer or employee of the Department of Parks and Recreation designated a peace officer by subdivision (g) of Section 830.2, any officer or employee of the Department of Fish and Game designated a peace officer under subdivision (f) of Section 830.2, and any publicly employed full-time lifeguard or publicly employed full-time marine safety officer while acting in a supervisory position in the performance of his or her official duties, may close the area where the menace exists for the duration thereof by means of ropes, markers, or guards to any and all persons not authorized by the lifeguard or officer to enter or remain within the enclosed area. If the calamity creates an immediate menace to the public health, the local health officer may close the area where the menace exists pursuant to the conditions set forth in this section.
(b) Officers of the California Highway Patrol, California State Police Division, police departments, marshal's office or sheriff's office, officers of the Department of Fish and Game designated as peace officers by subdivision (f) of Section 830.2, or officers of the Department of Forestry and Fire Protection designated as peace officers by subdivision (h) of Section 830.2 may close the immediate area surrounding any emergency field command post or any other command post activated for the purpose of abating any calamity enumerated in this section or any riot or other civil disturbance to any and all unauthorized persons pursuant to the conditions set forth in this section whether or not the field command post or other command post is located near to the actual calamity or riot or other civil disturbance.
(c) Any unauthorized person who willfully and knowingly enters an area closed pursuant to subdivision (a) or
(b) and who willfully remains within the area after receiving notice to evacuate or leave shall be guilty of a misdemeanor.
(d) Nothing in this section shall prevent a duly authorized representative of any news service, newspaper, or radio or television station or network from entering the areas closed pursuant to this section."