Judicial activism, while often lauded for its role in upholding justice and protecting fundamental rights, also presents several demerits that can undermine the foundational principles of a democratic system. Firstly, it can lead to the usurpation of powers and encroachment on the domains of the legislature and executive. When courts delve into policy-making or administrative functions, they effectively overstep their constitutional boundaries. This blurs the lines of separation of powers, a cornerstone of democratic governance, and can lead to a 'judicial overreach' where judges, not elected representatives, dictate policy, potentially undermining the will of the people as expressed through their elected government.

Secondly, a significant demerit is the lack of accountability of the judiciary. Unlike the executive and legislature, which are directly accountable to the electorate through elections, judges are not. When judges become actively involved in policy formulation or administration, they are making decisions that have broad societal impact without being subject to the same mechanisms of public scrutiny and accountability. This can lead to arbitrary decisions or those based on personal ideologies rather than broad public consensus, with limited avenues for redress or reversal by the populace.

Thirdly, judicial activism can result in populist judgments or a decline in judicial restraint, potentially leading to a perception of arbitrariness or a lack of legal certainty. In an attempt to address perceived societal wrongs, courts might issue directives that are difficult to implement, lack a strong legal basis, or are not well-thought-out in terms of their long-term consequences. This can strain the relationship between the judiciary and other branches of government, reduce the predictability of legal outcomes, and even lead to a 'tyranny of the judiciary' where judicial pronouncements, however well-intentioned, override the legitimate functions and expertise of other state organs.