The legislature separates powers in government by using a system of checks and balances. It means that each of the branches of government can limit the powers of the others. In that way the power is balanced. For instance, the president vetoes the bills but then the Congress needs percentage of 2/3 votes in order to pass that bill after the president's veto. Apart from that, the Supreme Court plays an important role because every bill must be evaluated by it. Only after that examination the bills are declared laws.