While emphasising that everything possible should be done to preserve and protect the judiciary, President Pranab Mukherjee on Saturday cautioned that judicial activism should not lead to erosion of the constitutional principle of separation of powers. The separation of powers was equally a principle of restraint. While the exercise of powers of the legislature and the executive was subject to judicial review, the only check on the judiciary’s exercise of powers was self-imposed discipline and self-restraint, he said, delivering the valedictory address at the sesquicentennial celebrations of the Madras High Court. He dealt with issues that have dominated the legal discourse in recent times such as judicial independence, judicial activism, judging the judges, speedy disposal of cases, filling of vacancies in courts and improving the quality of legal education. The judiciary’s independence was widely recognised and was a matter of pride. The judiciary had enlarged the scope of fundamental rights and increased the space for democracy, while maintaining the quality of justice, he said.