The court has found that there is no limit, other than economic, on the number of newspapers, books, magazines, or pamphlets that can be printed and circulated. But there is a physical limit on the number of television or radio stations that can operate in a given portion of the broadcast spectrum. Accordingly, said the Court, broadcasting is a public resource, much like the national parks or navigable rivers; this gives the government the right not only to allocate frequencies but also to set standards to ensure that their use will promote “the public convenience, interest, or necessity.”