he three branches of the federal government — legislative, executive, and judicial — operate within a constitutional system known as "checks and balances." This means that although each branch is formally separate from the other two, the Constitution often requires cooperation among the branches. Federal laws, for example, are passed by Congress and signed by the President. The judicial branch, in turn, has the authority to decide the constitutionality of federal laws and resolve other disputes over federal laws, but judges depend upon the executive branch to enforce court decisions.