A pedantic distinction between rhetoric and oratory is that the former is concerned with the theory of writing speeches, while the latter focuses on speeches as performative acts. The division is artificial and misleading. The distinction is one of etymology (the Greek rhetor vs the Latin orator), and is not one that the classics, who created the discipline and the art, were familiar with.
Rhetoric/oratory is an abiding legacy of the ancient world. Every culture has had its speeches, its deliveries, its persuasion and its way to talk the talk. The ancient Greeks and the Romans, however, made speeches central to life in the city. Rhetoric was a key ingredient to ancient education and was one of the catalysts of the Renaissance.
In classical rhetoric, the art of speech-writing was divided into judicial, deliberative and epideitic oratory. Judicial oratory, known also as forensic, focuses on past event, its purpose being to accuse or exculpate a person. Judicial oratory survives in the courts and in all other contexts where the objective is establishing guilt or innocence.
Deliberative oratory positions itself in the future and seeks to exhort or dissuade. The modern variant is the political debate, the pep talk, the pitch, the advertising campaign, the TED talk. According to Aristotle, the deliberative speech tries to establish whether something is good or unworthy, advantageous or disadvantageous.
Finally, epideictic oratory deals with speeches written and delivered for the here and now. The Greek ‘epideictic’ means ‘fit for display’ and is the type of speech best fit for praising or blaming an individual, a group or a situation. Bootlickers are experts of the epideictic mode, and so are those inveighing against someone or something. The best man’s speech at a wedding is a latter-day survival of epideictic rhetoric. So is the activist in the street denouncing the status quo. The three modes can overlap. The activist, while denouncing a situation, urges her supporters into action (deliberative mode) while at the same time assigning guilt to a politician or some other person (judicial mode).
Although rhetoric has survived in so many areas of modern life, the classical theory of rhetoric has broken down into two distinct species: on the one hand, the academic book about the topic, technical and often inaccessible to the general public; on the other, the self-help book, pitiful (re)digests of a noble art, but popular with most.