Radio and a rescue helicopter is my first choice. Failing that I would settle for a 44 mag revolver, Ruger Redhawk with 240 gr SJSP bullets and a 12 gauge with rifle sights and plenty of slugs. If it has to be a rifle my old antique M71 Winchester .348 with a bucket full of handloads using FP 250 gr bullets would suffice.
Good intentions will always be pleaded for any assumption of power. The Constitution was made to guard the people against the dangers of good intentions. There are men in all ages who mean to govern will, but they mean to govern. They promise to be good masters, but they mean to be masters.