In an adversary system of justice, the judgement of a court is essentially based on the arguments of lawyers representing the litigants. The evidences are rendered by the litigants. The burden of proof lies on the parties in the case. A judge hearing the case, acts like an umpire.
The role of a judge in adversary system can be better described by comparing it with the task of a cook. A cook before he or she put rice in the cooker undergoes a tedious job of observing each and every particle of the rice with an objective of separating stones and other things, if any, from the rice.
A case to be heard by a judge is something like rice before it is cooked. The dispute between the parties may comprise of multiple facts and variety of evidences. In many occasions, the facts are contradictory; the evidences are obscured, circumstantial, and indirect. Here is the role of a lawyer- he/she clarifies, interprets and proves the fact in favour of his/her client. He or she analyze the evidence and make decisive argument to win the case. In fact, it is the role of a lawyer that determines the justice.
It is a common saying that a lawyer can win a case on the strengths of his argument, not on the weaknesses of his counterpart. He is needed to be equipped with essential arts of advocacy, which involves many strategies and principles.