Corruption in a culture is corrosive in so many ways. Obviously it hurts the economy and the effectiveness of government in general. But it also tends to greatly reduce the effectiveness of the military. This is why nations with a lot of corruption tend to have multiple military organizations. The elite ones are treated generously and fairly and led by officers who are admired by their troops. These elite units are a minority and they exist, at great expense, to ensure the loyalty of the many “regular” units led by officers who steal whenever they can and really don’t care much about the welfare of their troops. This includes the police as well as the army, navy and air force. Leaders of corrupt nations see the military as a source of personal income not a defender of the nation. The troops are seen primarily as a way to keep the general population under control.
The military takes advantage of the corruption side effects (poor economy and high unemployment) by providing jobs. Not the greatest jobs, especially considering that the officers tend to be more concerned with stealing than developing a highly effective military unit. This last item explains the popularity of militias during a military emergency. That is why the importance of pro-government militias in Iraq are so important. The Iraqi military is largely run by incompetents and thieves. These are officers the troops have little faith in. The militias are led by men you can trust, otherwise these militias don’t exist. Most of the militias are created to defend a specific neighborhood and the members tend to know each other well. That includes the officers. Mistreating a neighbor or relative is less likely and for that reason in dangerous times, like Iraq after the ISIL (Islamic State in Iraq and the Levant) offensive in mid-2014. That offensive succeeded mainly because so many Iraqi soldiers deserted. Yet many of these “deserters” soon joined a militia. One benefit of all this was to force the government to eliminate the most incompetent officers and crack down on the corruption.
In autonomous northern Iraq the local Kurdish armed forces (the Peshmerga) began as clan militias and still retains the trust and effectiveness you get from organizations held together by bonds of family and neighborhood. Saudi Arabia took this to an extreme. Thus the Saudi military has about 200,000 troops. But 80,000 of those belong to a separate force, the National Guard. These are organized into eight brigades (three mechanized and five infantry, for a total of 32 battalions.) There are also another 24 battalions of National Guard reservists. About 75 percent of the National Guard troops spend most of their time guarding oil facilities, and other important government assets. The rest provide security for the royal family and key government officials. The most loyal, and able, members of the royal family hold senior commands in the National Guard. This is an organization that puts a lot of emphasis on loyalty. The National Guard is well armed and trained, all of them. But most of all, they are loyal to the royal family. But being that the country is called Saudi Arabia, after the ruling Saud family, the National Guard also protects the government. Since the Sauds see themselves, first and foremost, as the protectors of the most holy places in Islam (Mecca and Medina), the National Guard also serves God. So the National Guard is far more than tribal warriors loyal to a wealthy and generous family. The National Guard are holy warriors, who follow the protectors of the Islamic holy places. That's a big deal in Arabia, and the Islamic world. While the National Guard recruits first for loyalty, next comes bravery and willingness to die for the cause (the royal family and Islam.) Then comes military aptitude.