So far, the campaigns have focused on war costs and troop levels, while the Bush administration has focused on problems in the U.S.-Iraq status of forces agreement.
These are all important issues, but they disguise a much more critical reality. Iraq's destiny is not going to be shaped by U.S. policy and decisions, and its future is not going to be determined by U.S. goals in nation building. Iraqis already are taking charge of their own future in making a new Iraq - and it will not be the one the U.S. went to war to help create.
The reality is that no one knows, or can predict, the outcome of the U.S. intervention in Iraq, except to say that an uncertain military victory over al Qaeda in Iraq and over the insurgency is not victory in any grand strategic sense.
History provides countless warnings that states as divided and weak as Iraq is today rarely become stable - much less become stable, liberal democracies - without a long series of power struggles.
Iraq may well retain many elements of democracy, but it will not be a transformational example or model to anyone. Iraq faces a decade or more of painful adjustments and power struggles among Arabs, Kurds and other minorities.
Religion will continue to breed violence and struggles between Sunnis and Shi'ites as well as problems for Iraq's Christians. Intra-Shi'ite and intra-Sunni power struggles may be equally as serious in terms of shaping Iraq's future - and may do as much to cause violence. A strongman, strongmen or Shi'ite dominance can occur within a democratic context or create a new form of authoritarianism.
As for Iraq's neighbors, no one can predict how well Iran will be able to advance its own interests over time, how Turkey will deal with the Kurds or how the Arab world will see Iraq after - and if - new local elections occur.
As for spreading democracy to other Arab states, five years of insurgency, sectarian and ethnic conflict, casualties and displacements, public misery and bad governance are more likely to breed born-again monarchists - or at least acceptance of the status quo.
Future Iraqi regimes almost certainly will refuse to base U.S. forces and will not be a friend of Israel. Iraq will have lost a secular dictator but will become a far more religious state - albeit one split between Sunni and Shi'ite factions.
Economic development is at best nascent, and the U.S. will leave behind a state-dominated economy with a crippled petroleum sector and massive problems in unemployment and the distribution of income.
Al Qaeda in Iraq may be largely defeated, but it did not exist before the U.S. invasion, and Islamic extremism and violence will be stronger as a result of the war.
The key question for the next president is what his administration can do to influence Iraq, given all of these problems and constraints. Although there are no easy or "good" answers, there is much the next administration can do.
First, cooperate fully in cutting U.S. force levels and in showing Iraq and the region that the U.S. will leave and give up its bases in response to Iraqi demands. The U.S. should not rush out on its own or compromise the legal status of American troops and contractors, but it is better to take risks in cutting U.S. forces more quickly than to resist Iraqi political pressure and give Iran and America's Iraqi opponents more leverage.
Second, keep up the U.S. effort to encourage Iraqi political accommodation, to build effective Iraqi security forces and support Iraqi efforts to improve governance and Iraq's economy. Iraq may now need far less U.S. money than in the past, but it clearly still needs as much advisory support as possible. It is time to stop simply talking about "smart" and "soft" power and actually show patience in exercising it. The more the U.S. does to support Iraq without trying to control it, the more influence the U.S. will retain and the more it will do to limit sectarian and ethnic struggles.
Finally, the U.S. should work with Iraq's neighbors, the United Nations and other states to support Iraqi efforts to enhance its security, get outside aid and encourage development. One must beware of empty calls for regional cooperation and conferences, which will have cosmetic impact at best. Patient U.S. diplomacy with Turkey, Arab states and Europe, in cooperation with the United Nations, can have far more success, do more to moderate Iraq's internal struggles and show Iraqis the value of U.S. support.
Even the best mix of U.S. diplomatic and aid efforts, and support to Iraqi force development will not shape the Iraq that the U.S. wants or will not prevent a decade to a quarter-century of uncertainty and instability. It does, however, offer the best real-world hope of turning the Iraq war into some form of grand strategic success.
• Anthony H. Cordesman holds the Arleigh A. Burke Chair in Strategy at the Center for Strategic and International Studies.