Occasionally, news from those wars comes with a shock of absolute recognition, as when it was revealed ― after the Islamic State offensive in Iraq exploded in the fall of 2014 and city after city fell to relatively small groups of militants ― that the American-trained Iraqi army’s real strength was far lower than its strength on paper. That was because as many as 50,000 of the troops on that army’s rosters ― the equivalent of four full divisions ― were “ghost soldiers,” men who did not actually exist or had deserted but were still being paid, with their commanders pocketing their salaries. The city of Mosul, for example, was ostensibly defended by 25,000 government troops when the Islamic State militants attacked. The actual number was less than half that many ― in some units, an even smaller fraction. This, it should be noted, in a force that had received something like $25 billion in U.S. support in the decade after the 2003 invasion.
Source : https://www.huffingtonpost.com/entry/in-present-american-wars-repeating-past-mistakes_us_5ae9ff86e4b081860d8ca158