Vast tracts of our most treasured public lands, supposedly set aside in perpetuity for Americans, are no longer controlled by the United States government. Instead, they have been invaded and taken over by Mexico’s violent criminal drug organizations to grow marijuana. Even more shocking: Mexican cartels have been growing marijuana for at least 10 years in Sequoia National Park, one of the crown jewels of the system. Nature-loving hikers are compelled to accept that parts of Sequoia are "no go zones" during the growing season. These Mexican marijuana messes are an ecological disaster. They are not innocent little plots that...