When a bill passed by legislature is vetoed by the executive, the action underscores the principle of

The veto of a bill by the executive underscores the principle of "checks and balances". Checks and balances means that the power is divided among different branches of government, so that no one branch becomes too powerful. In this case, the legislative branch has passed a bill, but the executive branch has the power to veto it, which acts as a check on the legislative branch's power. This system of checks and balances helps to ensure that government power is not concentrated in any one branch, and helps to maintain a balance of power between the branches.