Let me start with quoting Nixon's policy on Vietnamization, and how we see parallels to Iraq today.
In his first term, Nixon carried out a policy of "Vietnamization," whereby many U.S. troops were withdrawn from Vietnam and replaced by members of the South Vietnamese army. Nonetheless, American troops remained on the ground and the Nixon administration continued to provide supplies and air support for the Vietnamese, and expanded the war into Laos and Cambodia [Link]
Vietnamization failed badly. Is Iraq with an incredibly fragile, yet sincere local infrastructure but totally besieged by malignant internal strife headed for Vietnamization? That is a sobering thought and seems to be no simple answers at present. Something that cannot be untangled with the issue at hand today or immediately.