Why is it that those seeking to overthrow a government can often do it without outside help other than weapons, but that government forces need outside advisers?
We saw it in Viet Nam where the Viet Cong kept fighting and fighting against both the South Vietnamese government and their U.S. advisers. It got to the point where the "advisors" were doing more of the fighting than the government forces.
We saw it in Iraq where a large variety of "insurgents" fought against the foreign invaders and then against the Iraqi government as well as each other. The outside invaders stayed to advise the new government, but that government seems ineffectual against the "insurgents".
We see it in Afghanistan where the Taliban keeps striking at the foreign invaders/advisers and the Afghan government, including local governors as well as the Afghan army and police.
Could the common thread be that all these governments were not only corrupt but not fully supported by the general populations? Could it be that the only way to put down anti-government forces is to have a strong, dictatorial government or to have wide-spread popular support of a freely elected government?
And a freely elected government cannot really be imposed from outside.