Who is Sandy Stern from Presumed Innocent and what is their importance?

Alejandro "Sandy" Stern is Rusty's defense attorney. An Argentinian Jew and a Spanish gentlemen, he is elegant, erudite, courtly, soft-spoken, and beautifully manicured. Physically, he is short, roundish, and balding. As a trial lawyer, Sandy is low-key, fastidious, and extremely adept, with an instinct for divining the characters of people. In court, he seems to concentrate as much on figuring out the psychology of a witness as he does on the facts themselves. He's secretive about facts, but well-connected, and seems to find out almost everything about a case. Sandy does not like describing his strategy, even to his client, and he hates making predictions or any other statement that might backfire on him. If necessary, he will take a chance in court. Stern does not always err on the side of caution, but the chances he takes are well-calculated.