Answer:
Political, government, and legal systems are held accountable by laws because the laws themselves establish the nature, characteristics, duties, and limits of those systems.
Step-by-step explanation:
The best example of this is the constitution of a state. The constitution is the supreme law of the land, from which all other laws are derived. Constitutions develop the political, goverment, and legal systems to be applied in their juridisticions, and also determine the limits to the power of each of these system.
A more concrete example is the U.S. Constitution, which establishes the political system: a republic, the government system: a government divided in three branches: the executive, the legislative, and the judiciary, and the legal system: common law.