In a presidential system, the president is often elected directly by the people. This makes the president's power more legitimate than that of a leader appointed indirectly. However, this is not a necessary property of a presidential system. Some presidential states have an unelected or indirectly elected head of state.
A presidential system establishes the presidency and the legislature as two parallel structures. This arrangement allows each structure to monitor and check the other, preventing abuses.
A president with strong powers can usually enact changes quickly.
A president, by virtue of a fixed term, may provide more stability than a prime minister who can be dismissed at any time.
In most presidential systems, the president is elected by popular vote, although some such as the United States use an electoral college (which is itself directly elected) or some other method. By this method, the president receives a personal mandate to lead the country, whereas in a parliamentary system a candidate might only receive a personal mandate to represent a constituency. Since prime ministers are not elected directly, it could be argued their mandate to lead is not a personal mandate and therefore less legitimate. A presidential system separates the executive from the legislature is sometimes held up as an advantage, in that each branch may scrutinize the actions of the other. In a parliamentary system, the executive is drawn from the legislature, making criticism of one by the other considerably less likely. Presidential systems can respond more rapidly to emerging situations than parliamentary ones. A prime minister, when taking action, needs to retain the support of the legislature, but a president is often less constrained.
When parliamentary systems have multiple parties and governments are forced to