It is called presidentialism to the political system whose organization is based on the performance of the President What goverment’s head, without needing the support of the legislative chambers. Thus, the president is the formal representative of the nation and the head of the executive branch.
A presidential regime is framed in a republic, since the authorities are chosen by the Parliament or by the citizenship to exercise their mandate for a certain period of time. It is important to bear in mind that, in the republics, there is a division of powers through the power of attorney, the legislative power and the executive power.
The president, in a presidential system, is directly elected by the people through an electoral process and directs the executive power according to the attributions granted by the Constitution.
It should be borne in mind that, although the legislative power and the executive power are independent, the president has certain special legislative powers. On Argentina, for example, the president can sign Necessity and Urgency Decree, which are standards with a range of law.
With presidentialism, in short, executive power rests with the president, appointed by the citizens through the Universal suffrage. The president coexists in power with the Congress (or Parliament), which cannot take away the authority of the president except for certain exceptions. This means that the president does not need the trust or support of Congress to lead the government.
Political science experts often mention that, among the advantages that presidentialism offers over others systems, the stability of the head of government and the speed with which he can make decisions and implement his measures stand out.