Iraqi commanders (military and police) who have worked with American troops and advisors for years, fear that the improvements to the Iraqi security forces (better training, leadership and readiness) will disappear once the Americans are gone. The reason, in a word, is corruption. The politicians running the ministries of Defense and Interior are fine with doing business the old fashioned way. That is, stealing at every opportunity. The assessment is based on the fact that many Iraqi military and police commanders still have to call on their American advisors or counterparts, to intervene when the ministry refuses to supply things needed for training (fuel, ammunition or money for maintaining equipment and facilities.) The ministry refuses because these things cost money, which they feel is better off in their offshore bank accounts, or used to hire political hacks, who will help keep the politician in office.
In theory, the ministries agree with the Americans; that effective training is expensive. But in practice, the ministries can't wait for the Americans to leave. Then there will be no one to blow the whistle (or threaten to do so) when the cash for training mysteriously dries up (even if it is the U.S. that is supplying it.) It will also be easier to go back the ancient and profitable practice of extracting bribes from subordinate commanders, including those who run the training establishments. Currently, the only way you can punish these fellows for not paying, is to block their promotions. Only team players are wanted in the higher echelons of the ministries. And once the Americans are gone, everyone will have to play by Middle Eastern rules. U.S. commanders believe that their Iraqi counterparts are being too pessimistic, while the Iraqis accuse the Americans of being too optimistic.