What is forensic oratory?

John Quincy Adams, answered from the texts and cited to the page.

John Quincy Adams answers

Forensic oratory — the oratory of the courts — is that branch of the art whose proper scene is the tribunal, and whose proper question is not what shall be done, but what was done; not the useful, but the just.¹ The ancient rhetoricians divided all oratorical performance into three great classes: the demonstrative, concerned with praise and blame; the deliberative, concerned with what shall be enacted or resolved; and the judicial, or forensic, concerned with past action brought before a competent authority for judgment.²

The division is not arbitrary. It follows from the nature of the occasion itself: before a popular assembly, the orator deliberates upon something yet to be determined; before a tribunal, the question is already fixed by the act alleged, and the whole exertion of counsel must be to bring the cause into conformity with the standard of justice.³

Now here is the point on which forensic oratory differs most materially from the other two branches, and it is a point I pressed upon my students at Cambridge with some earnestness. Demonstrative and deliberative oratory are not of necessity connected with any particular social institutions; an eulogy may be pronounced by a citizen of one nation upon the subject of another, and deliberation may occur between persons bound by no social compact together.⁴

But judicial eloquence is inseparable from positive institution. Under our improved theories of natural and social rights, every trial is neither more nor less than a conflict between law and transgression; to try a man by the laws of one nation for an offence against the laws of another would be at once the extreme of oppression and the height of absurdity.⁵

The common standard by which all judicial argument must be measured is law; the whole drift of an advocate's eloquence, to display the conformity between the cause of his client and the law; the whole purpose of a prosecutor, to vindicate its violation; the whole defence of innocence, to disprove its infringement.⁶ Within that framework, the forensic speaker must attend to three particulars of especial importance in our institutions: the division of all offences into public and private wrongs, with the consequent distinction between criminal and civil jurisdiction; the further division of public wrongs into personal offences and official crimes triable by impeachment; and the division of powers between judge and jury, with the pardoning power separated from both.⁷

When the issue turns upon fact, the advocate examines witnesses and marshals evidence; when it turns upon a point of law, there are no witnesses — the controversy resolves itself into the question of what the law is and how it applies, governed by natural justice, immemorial usage, statute, or the precedents of prior adjudication.⁸ Where none of these bears with direct and literal proof upon the cause, the reasoning must proceed from analogy, and counsel on both sides must recur to all the resources of ratiocination and induction that the science of argument affords.⁹

That is forensic oratory: the art of the bar, bounded by law, directed at justice, and governed at every point by the institutions of the society in which it is practised.

Sources

Before the public tribunals, where the litigation of conflicting rights was conducted, the question must necessarily concern some action past; and the common standard, to which the orator must exert himself to bring the cause, which he supported, was justice.
Lectures on Rhetoric and Oratory, Vol 1
I indicated the three great classes, into which all oratorical performances were divided by the ancient rhetoricians, and by them denominated the demonstrative, the deliberative, and the judicial.
Lectures on Rhetoric and Oratory, Vol 1
In the popular assemblies, general or particular, the subjects discussed were concerning laws to be enacted, taxes to be levied, distributions of the public force and revenue to be made... Deliberation upon something to be done was the common character of all such meetings.
Lectures on Rhetoric and Oratory, Vol 1
Demonstrative and deliberative oratory are not of necessity connected with any particular social institutions... An eulogy or a philippic may be pronounced by an individual of one nation upon the subject of another. Deliberation may occur between persons, bound by no social compact together.
Lectures on Rhetoric and Oratory, Vol 1
To try a man by the laws of one nation for an offence against the laws of another would be at once the extreme of oppression and the height of absurdity.
Lectures on Rhetoric and Oratory, Vol 1
The common standard then, by which all judicial argument must be measured, is law; the whole drift of an advocate's eloquence, to display the conformity between the cause of his client and the law; the whole purpose of a prosecutor, to vindicate its violation; the whole defence of innocence, to disprove its infringement.
Lectures on Rhetoric and Oratory, Vol 1
Now the particulars in our judicial institutions of the most material importance to the forensic speaker are three. 1. The division of all offences against the laws into public and private wrongs... 2. The division of public wrongs into two classes... 3. The division of powers... between the judges and jury.
Lectures on Rhetoric and Oratory, Vol 1
If the issue of the cause be taken upon a point of law, the defence must be conducted upon principles entirely different. In such cases there is no examination of witnesses. The controversy turns upon the law and its construction; and the reasoning is restricted to inquiries, what the law is, and what is its application to the cause upon trial.
Lectures on Rhetoric and Oratory, Vol 2
the reasoning must be from analogy; and the defendant, as well as the plaintiff, must recur to all those resources of ratiocination and of induction, upon which I so largely dwelt in my two preceding lectures.
Lectures on Rhetoric and Oratory, Vol 2