Why might a commitment to law and justice be considered rome's greatest legacy?

Answer is: Roman law is backbone of todays Europe and Us.
Roman law and legal system is applied in most Europe and also in US. Today, many rules deriving from Roman law. Romans also had unity and stability, Senate had more power and they had strong republic government.

B) The fall of the Berlin wall stopped the separation of the communist east Berlin and the other half of the city, controlled by the US.