One of the great impediments to enacting a lawyer in a courtroom scene is the overwhelming seduction of advance knowledge and superiority.
Nothing (and no one) on stage is more boring than someone who knows everything; and yet, in everyday life, a good lawyer is admonished: "Never ask a question of a witness that you don't already have the answer." So when playing a lawyer, how does one avoid the risk of losing many, many of the elements of good acting: surprise, moment-to-moment dialogue (living life without any foreknowledge of what is going to be said and done next), etc.
How does a good actor combine the truth of lawyer courtroom questioning with the good acting habits of actor innocence and perpetual freshness? The answer lies in lawyer reality of the courtroom progress itself: in the very fiction
that is basic to the practice courtroom law, the very fiction that lies at the heart and soul of the adversarial system of the law: the lawyer is an officer of the court, a seeker of truth, not merely a purveyor of adversarial advantage. In this 'legal-fiction' light lawyers on either side of a case are bulwarks of the truth-seeking nature of the judicial system, adversarial in structure, true, but obedient to a higher function: the pursuit of overarching truth and its twin-sister, justice. That's why lawyers seek to avoid knowing--and as a corallary, assiduously avoid their clients ever telling them --they are guilty (or, on the other hand finding out they are innocent when the lawyer is a prosecutor). If they know their client is guilty (or innocent) they are honor bound to reveal their knowledge, to notify the system. Running parallel to this, all evidence must be shared by opposing counsels, etc....as part of maintaining that fiction
of objectivity. the fiction
of both sides of the legal line being, above all, 'officers of the court'.
So, the smart lawyer--and the smart actor playing a lawyer--uses this fiction of impartiality to his or her best arguing advantage: in questioning a witness they 'act' as if they know nothing. They are just 'good old boys' (or 'girls'), asking the witness to help them through their confusion about the facts. The 'act' as if they are as innocent and guileless as the jury; in fact, they act as if they are the 13th member of the jury, only trying to ascertain truth and bring about justice!
So when playing a lawyer (or, in fact, being one in everyday litigating): ask every question (of every witness) as if you know nothing. 'Act' in questioning not as a lawyer but as an officer of the court, as one who is confused, who needs the witness's help in your moving from confusion to clarity, who asks these questions only to the witness's help to 'connect the dots of justice', as it were.
And the lawyer or lawyer-actor who does this, 'acts' as an officer of the court, even if the most strenuous cross-examination, will maximize attractive sympathy, whether from a courtroom just or a 'jury' of an audience; and ears, ears and dramatic identification will flow to the innocent questioner (the good actor) who pursues only the advancement of dramatic/legal truth and justice, and does not know--like the jury--the answer to the next question!