Checks and balances in government describe the various mechanisms put into place by the constitution to check all powers of government and ensure there is no one person dictatorship.
Under separation of powers, all arms of government check each other's power to achieve a sort of balance that makes sure power is distributed and equality among the three tiers is achieved.
The legislative makes laws and the executive can veto certain laws by the legislative while the judiciary which is responsible for enforcing these laws may declare these laws unconstitutional and void. The legislative may also check the veto powers of the executive by amassing a two thirds supermajority(under U. S laws) by both houses of Congress to vote and therefore neutralize this power. This keeps the executive from arbitrarily and unjustifiably using his veto powers.
