If you look at the past and present records of Washington's foreign interventions, it's clear that Washington has been best at helping pro-Washington regimes suppress domestic challengers, that it has been better at subversions (from Iran, Guatemala, Chile, and Afghanistan to Yugoslavia, Georgia, and Ukraine) than invasions, and that the peoples targeted by it (with the great exceptions of Cubans and Venezuelans) have been generally better at fighting against its invasions than protecting their governments from its subversions or overthrowing pro-Washington regimes.
Having learned from its study of activists and organizers on the left, Washington (mainly through its "civil society" fronts, such as the National Endowment for Democracy, the AFL-CIO's international department, Freedom House, the National Democratic Institute for International Affairs, the International Republican Institute, the Open Society Institute, and so on) has almost perfected the art of subversions.
In contrast, when Washington actually invaded nations bigger than Grenada and Panama, it either couldn't achieve its maximum objective (Korea) or suffered an ignominious defeat (Vietnam) or beat hasty retreats (Lebanon, Somalia).
Check out the Army's "Field Manual–Interim No. 3-07.22" (October 1, 2004-October 1, 2006), a manual for counterinsurgency operations. The manual recognizes political reality: "One of the key recurring lessons is that the United States cannot win other countries’ wars for them, but can certainly help legitimate foreign governments overcome attempts to overthrow them. US forces can assist a country confronted by an insurgency by providing a safe and secure environment at the local level and continuously building on the incremental success" (emphasis added, October 1, 2004-October 1, 2006, p. vi). In other words, Washington cannot win its counterinsurgency war against Iraqi resistance fighters, unless it succeeds in installing a pro-Washington regime that enjoys more legitimacy in the eyes of Iraqis than its puppet regime headed by Ngo Dinh Diem and Nguyen Van Thieu in southern Vietnam did in the eyes of the Vietnamese.
So far, Iraqification, plagued by desertions, has failed, and Ayad Allawi, in whom Iraqis had little faith to begin with (only 27% of Iraqis approved the formation of his cabinet in the first post-"hand-over" poll that the Iraqi Center for Strategic Research and Studies conducted in seven major cities), probably lost any chance of winning the hearts and minds of Iraqis after Falluja (Hannah Allam and Jonathan Landay/Knight Ridder, "Fallujah Battle May Carry Heavy Political Price for Iraqi Government," November 14, 2004). Washington's hope is that the United Iraqi Alliance, a list mainly composed of Shiite political leaders and backed by Ayatollah Ali al-Hussein al-Sistani, (Robert F. Worth/New York Times, "Iraqi Shiites form Election Alliance; Pullout Talks a Goal," December 10, 2004), will be the pro-Washington regime that it desperately needs.
The fate of the January elections is uncertain, and probably few Sunnis will vote (Adnan Pachachi predicts "no more than a 5 percent turnout in Sunni-dominated areas of Mosul, to the north, and in Anbar Province, west of Baghdad" [Worth, December 10, 2004], for instance), but there is no question that the electoral charade stalled the development of Sunni-Shiite unity seen in April.
Nevertheless, no election organized by a belligerent occupiers can be truly free, and no regime established through one is unlikely to survive without the occupiers' direct military support.