A constitutional government is characterized as a limited government because it operates within the framework of laws and principles established by a constitution, which restricts the powers of the government and protects individual rights. This design prevents arbitrary rule and ensures accountability, thereby promoting democratic governance and the rule of law. In the context of UPSC Prelims, understanding the essence of constitutionalism emphasizes the importance of checks and balances, reinforcing the idea that government authority is derived from and constrained by legal norms rather than being absolute.