In the 7th millennium BC ecological conditions in the northern half of Chadian territory favored human settlement, and the region experienced a strong population increase. Some of the most important African archaeological sites are found in Chad, mainly in the Borkou-Ennedi-Tibesti Region; some date to earlier than 2000 BC.
For more than 2000 years, the Chadian Basin has been inhabited by agricultural and sedentary peoples. The region became a crossroads of civilizations. The earliest of these were the legendary Sao, known from artifacts and oral histories. The Sao fell to the Kanem Empire, the first and longest-lasting of the empires that developed in Chad's Sahelian strip by the end of the 1st millennium AD. The power of Kanem and its successors was based on control of the trans-Saharan trade routes that passed through the region. These states, at least tacitly Muslim, never extended their control to the southern grasslands except to raid for slaves.
French colonial expansion led to the creation of the Territoire Militaire des Pays et Protectorats du Tchad in 1900. By 1920, France had secured full control of the colony and incorporated it as part of French Equatorial Africa. French rule in Chad was characterised by an absence of policies to unify the territory and sluggish modernisation. The French primarily viewed the colony as an unimportant source of untrained labour and raw cotton; France introduced large-scale cotton production in 1929. The colonial administration in Chad was critically understaffed and had to rely on the dregs of the French civil service. Only the south was governed effectively; French presence in the north and east was nominal. The educational system suffered from this neglect.
After World War II, France granted Chad the status of overseas territory and its inhabitants the right to elect representatives to the French National Assembly and a Chadian assembly. The largest political party was the Chadian Progressive Party (PPT), based in the southern half of the colony. Chad was granted independence on August 11, 1960 with the PPT's leader, François Tombalbaye, as its first president.
Two years later, Tombalbaye banned opposition parties and established a one-party system. Tombalbaye's autocratic rule and insensitive mismanagement exacerbated interethnic tensions. In 1965 Muslims began a civil war. Tombalbaye was overthrown and killed in 1975, but the insurgency continued. In 1979 the rebel factions conquered the capital, and all central authority in the country collapsed. Armed factions, many from the north's rebellion, contended for power.
The disintegration of Chad caused the collapse of France's position in the country. Libya moved to fill the power vacuum and became involved in Chad's civil war. Libya's adventure ended in disaster in 1987; the French-supported president, Hissène Habré, evoked a united response from Chadians of a kind never seen before and forced the Libyan army off Chadian soil.
Habré consolidated his dictatorship through a power system that relied on corruption and violence; an estimated 40,000 people were killed under his rule. The president favoured his own Daza ethnic group and discriminated against his former allies, the Zaghawa. His general, Idriss Déby, overthrew him in 1990.
Déby attempted to reconcile the rebel groups and reintroduced multiparty politics. Chadians approved a new constitution by referendum, and in 1996, Déby easily won a competitive presidential election. He won a second term five years later. Oil exploitation began in Chad in 2003, bringing with it hopes that Chad would at last have some chances of peace and prosperity. Instead, internal dissent worsened, and a new civil war broke out. Déby unilaterally modified the constitution to remove the two-term limit on the presidency; this caused an uproar among the civil society and opposition parties. In 2006 Déby won a third mandate in elections that the opposition boycotted. Ethnic violence in eastern Chad has increased; the United Nations High Commissioner for Refugees has warned that a genocide like that in Darfur may yet occur in Chad.
Chad's constitution provides for a strong executive branch headed by a president who dominates the political system. The president has the power to appoint the prime minister and the cabinet, and exercises considerable influence over appointments of judges, generals, provincial officials and heads of Chad's para-statal firms. In cases of grave and immediate threat, the president, in consultation with the National Assembly, may declare a state of emergency. The president is directly elected by popular vote for a five-year term; in 2005 constitutional term limits were removed.
This removal allows a president to remain in power beyond the previous two-term limit. Most of Déby's key advisers are members of the Zaghawa ethnic group, although southern and opposition personalities are represented in government.
Corruption is rife at all levels; Transparency International's Corruption Perceptions Index for 2005 named Chad the most corrupt country in the world, and it has fared only slightly better in the following years. In 2007, it scored 1.8 out of 10 on the Corruption Perceptions Index (with 10 being the least corrupt). Only Tonga, Uzbekistan, Haiti, Iraq, Myanmar, and Somalia scored lower. Critics of President Déby have accused him of cronyism and tribalism.
Chad's legal system is based on French civil law and Chadian customary law where the latter does not interfere with public order or constitutional guarantees of equality. Despite the constitution's guarantee of judicial independence, the president names most key judicial officials. The legal system's highest jurisdictions, the Supreme Court and the Constitutional Council, have become fully operational since 2000. The Supreme Court is made up of a chief justice, named by the president, and 15 councillors, appointed for life by the president and the National Assembly. The Constitutional Court is headed by nine judges elected to nine-year terms. It has the power to review legislation, treaties and international agreements prior to their adoption.
The National Assembly makes legislation. The body consists of 155 members elected for four-year terms who meet three times per year. The Assembly holds regular sessions twice a year, starting in March and October, and can hold special sessions when called by the prime minister. Deputies elect a National Assembly president every two years. The president must sign or reject newly passed laws within 15 days. The National Assembly must approve the prime minister's plan of government and may force the prime minister to resign through a majority vote of no confidence. However, if the National Assembly rejects the executive branch's programme twice in one year, the president may disband the Assembly and call for new legislative elections. In practice, the president exercises considerable influence over the National Assembly through his party, the Patriotic Salvation Movement (MPS), which holds a large majority.
Until the legalisation of opposition parties in 1992, Déby's MPS was the sole legal party in Chad. Since, 78 registered political parties have become active. In 2005, opposition parties and human rights organisations supported the boycott of the constitutional referendum that allowed Déby to stand for re-election for a third term amid reports of widespread irregularities in voter registration and government censorship of independent media outlets during the campaign. Correspondents judged the 2006 presidential elections a mere formality, as the opposition deemed the polls a farce and boycotted.
Déby faces armed opposition from groups who are deeply divided by leadership clashes but united in their intention to overthrow him. These forces stormed the capital on April 13, 2006, but were ultimately repelled. Chad's greatest foreign influence is France, which maintains 1,000 troops in the country. Déby relies on the French to help repel the rebels, and France gives the Chadian army logistical and intelligence support for fear of a complete collapse of regional stability. Nevertheless, Franco-Chadian relations were soured by the granting of oil drilling rights to the American Exxon company in 1999.
Educators face considerable challenges due to the nation's dispersed population and a certain degree of reluctance on the part of parents to send their children to school. Although attendance is compulsory, only 68% of boys attend primary school, and more than half of the population is illiterate. Higher education is provided at the University of N'Djamena.
According to the United Nations, Chad has been affected by a humanitarian crisis since at least 2001. As of 2008, the country of Chad hosts over 280,000 refugees from the Sudan's Darfur region, over 55,000 from the Central African Republic, as well as over 170,000 internally displaced persons.
In February 2008 in the aftermath of the battle of N'Djamena, UN Under-Secretary-General for Humanitarian Affairs John Holmes expressed "extreme concern" that the crisis would have a negative effect on the ability of humanitarians to deliver life-saving assistance to half a million beneficiaries, most of whom – according to him – heavily rely on humanitarian aid for their survival. UN spokesperson Maurizio Giuliano stated to The Washington Post: "If we do not manage to provide aid at sufficient levels, the humanitarian crisis might become a humanitarian catastrophe".