In expanding on what the government of an Islamic state should look like in his book "The Islamic Law and Constitution", Maududi took as his model the government of Muhammad and the first four caliphs ("al-Khulafāʾu ar-Rāshidūn"). The head of state should be the supreme head of legislature, executive and judiciary alike, but under him these three organs should function "separately and independently of one another." This head of state should be elected and must enjoy the country's confidence, but he is not limited to terms in office. No one is allowed to nominate him for the office, nor to engage in electioneering or run for office, according to another source.