The constitution is the highest law. Thus it is highly essential for this document to guard the fundamental rights of people and their freedom.
Constitution does have four essential practices, that ensure the impossibility of tyranny.
Federalism. It gives power to the states, instead of concentrating all the power in some sort of central government. Thus the branches of the government are divided, and it is considered to be the best guard against the tyranny of one central power.
Checks and balances. One branch of power is capable or even obliged to check the other. Such tests aim to ensure that they have equal power. Also, one branch can disapprove something done by the other if that violated the law, or approve something done if that was up to the law.
Equal representation from all states, both small and large. Each state is obliged to have at least one representative, but there shouldn’t be more than one representative for every 30,000. Each representative has equal rights in the government.
The division of government branches. It means there should be various distinctive branches or departments of government. Those different departments might have different viewpoints and thus ensuring the ability of people to take over some essential issues and meet legal support.
The constitution is considered to be the guard of society against tyranny, as it vanishes even the tiniest possibility of its occurrence.