All of the arts are kin - music and sculpture and dance, those are wordless art forms. But poetry is defined by language. Of course, each art is distinct, and has its own character - not just in terms of media, but in terms of what seems to lie at the heart of it.
Those in power need checks and restraints lest they come to identify the common good for their own tastes and desires, and their continuation in office as essential to the preservation of the nation.