Sierra Leone is an example of a country with political failures

as the lack of functioning institutions and overabundance of diamonds has fueled decades of civil war and corruption
as its economic growth has stagnated since it was colonized by the Ottoman Empire
as the post-independence government has restricted all economic activities and markets
as it is ten times poorer than its nearest neighbor

As the lack of functioning institution.

Explanation:

During the 17 year reign of Siaka Stevens which was tagged 17 years of plague of locust witnessed the destruction of institutions in Sierra Leone. Judiciary was undermined and corrupted, police and military was used as instrument of cohesion, the treasury was looted through sponsoring of pet projects to political insiders. Opponents were either sanctioned or sent on exile. Siaka Stevens was authority to himself.

When Siaka Stevens handed over to Major General Joseph Momoh, who was grossly inept and lack any sense of leadership, things went from bad to worse. Basic needs like goseline were in short supplies, government could not pay salaries. Every available resources was up for looting and these went on unchecked. At a time the schools closed as government could not pay school teachers. The bulk of her youth were uneducated and while the educated ones left the country in search of greener pastures.

In 1991 Sierra Leone was named the poorest country in the world despite having large deposites of gold, diamond, bauxite, iron ore, cocoa etc.