George Soros says investment is alchemy, not science. Big enough investments, made with lots of fanfare, are likely to draw in other investors after them, and thus succeed.

The administration did this with the bank bailouts, but it is doing the opposite in Iraq and Afghanistan. It's going to make an investment, of money and lives for years to come, but it seems to prefer not to talk about it. That's a pity, because this silence raises the risk that Iraqis' and Afghans' panic and despair will make that investment fail.

Some people think the U.S. administration is bound to refuse Iraqis' requests for American troops to stay there after 2011. That's not clear from its public reactions to the latest requests, from the unlikely duo of Tariq Aziz and Babiker Zebari -- that is, Saddam's former deputy and an anti-Saddam rebel who now heads the Iraqi armed forces. 

Instead Defense Secretary Robert Gates, the U.S. official most outspokenly in favor of a longer-term presence in Iraq, said "If a new government is formed there and they want to talk about beyond 2011, we're obviously open to that discussion." His stance reflects the U.S. military's interest in keeping a continued foothold in Iraq. But no definitive rebuttal has come from any other official source.

If troops do stay -- as in reality some must, to protect the billion-dollar Embassy if nothing else -- it will be for non-combat purposes such as training and logistic support for the Iraqi army. But even so, these troops will need to be able to defend themselves, they will need sufficient air transport to enter and leave in a hurry, and they will need fighter aircraft to protect their transport aircraft. They will have their own bases.  Gates said in 2008, in fact, that tens of thousands of troops might stay after 2011. 

If things go wrong subsequently -- if, for instance, Kurdish-Arab differences erupt into violence near Mosul after 2011 -- U.S. forces will not in practice be able to sit in their bases and do nothing. As Gen. Stanley McChrystal once said, the military do not want their bases to be surrounded by "Chaosistan" -- nor to have a repeat of the Tehran hostage crisis of 1979. The chances are high that if violence seemed about to engulf the country, the United States would take some action, even if just airstrikes and diplomacy.

In light of this sustained presence in Iraq, what should be on the table with a new Iraqi government is not just an offer to keep some U.S. troops in the country, but a security guarantee of the same kind that was given to Japan in 1951: "Each Party recognizes that an armed attack against either Party in the territories under the administration of Japan would be dangerous to its own peace and safety and declares that it would act to meet the common danger in accordance with its constitutional provisions and processes."

Such an undertaking represents what the United States will need to do, for its own interests, even without regard to the moral liability the United States and its allies have acquired for Iraq's suffering. By making it clear beforehand that this is the situation, the United States will reduce the risk of a spiral of violence or an invasion by Turkish or Iranian forces, by making it clear that the Baghdad government is not up for grabs.

So if such a guarantee makes sense for Iraq, why not for Afghanistan? The United States will always want to keep a presence in Afghanistan sufficient to carry out counter-terrorism operations, which implies a need for some military bases and a security agreement with the government in Kabul. So the U.S. military will have to be ready, there too, to face Gen. McChrystal's "Chaosistan" scenario. If an armed faction marches on Kabul to overthrow the Afghan government while U.S. forces are present in the country, will those forces just stay in their bases and watch? If they do, how will they be able afterwards to protect themselves and their supply lines -- and prevent a recurrence of the 1979 Iranian hostage crisis? And then what will the United States do if al-Qaeda returns to Afghanistan? Will it have to invade again?

Again, the United States will have to intervene as a final resort to protect a friendly government in Kabul from violent overthrow -- and it makes sense in the meantime for it to offer training and air support to the nascent Afghan military. And since U.S. forces will need to protect Afghanistan's security anyway, they may as well formally guarantee it. The small extra step this involves will be more than justified by the confidence it will give to the Afghans, calming their worst fears of as the aftermath of a U.S. drawdown starting next year.

Such a commitment from the United States would act as a significant deterrent to any armed faction that might otherwise hope to overthrow the government in Kabul. Nor would it be hard to do, legally speaking.  Unlike Iraq, the Afghan Government has not asked for U.S. troops to withdraw, nor is the Obama administration committed to a definitive drawdown.  There is even already a legal basis for a continuing U.S. presence in the form of the exchange of notes on the subject between the U.S. and the Afghan government in 2002 and 2003.

It is true that the Afghan government seems committed to talks with the Taliban, and that the Taliban have said that the withdrawal of U.S. troops is a precondition for such talks. But if those talks end up bringing the Taliban inside the government, even they might want U.S. forces to guarantee Afghanistan's stability. My colleague, the Taliban expert Michael Semple, believes that, "when [the Taliban] are in the political setup, it will be a different ball game. They will certainly be looking for an end to U.S. troops' combat role. But they understand Afghanistan is in an unstable part of the world."

It might be different if there were alternatives. A senior Pakistani diplomat suggested to me that U.N. peacekeeping forces would be more acceptable than U.S.-led ones; another commentator suggested Islamic forces should provide security in Afghanistan.  But as in the case of Iraq, there don't seem to be many volunteers to send troops, and even under a U.N. aegis this kind of operation seems unlikely. The biggest troop contributors to U.N. peacekeeping missions are in any case India, Bangladesh and Pakistan. None would be perceived as neutral.

The risk of a U.S. guarantee (much as some would say about the bank bailout) is that it absolves the Afghan government from the need to tackle corruption, poor citizen morale and bad or weak governance. So, as a second step to securing Afghanistan's future, the United States should demand, in return for a security guarantee, that Afghan President Hamid Karzai implement a genuine reform package by the time he leaves office in 2014. This package would include constitutional reform, a thorough drive to end corruption, and a settlement with the Taliban that serves the U.S. counter-terrorism effort. 

Once that initial reform package is in place and the security commitment is given, the U.S. government should still maintain a check on the Afghan government by basing financial assistance on further implementation of reforms. When U.S. forces are no longer exposed to the same level of risk, U.S. funds (both military and USAID funds) ought to become genuinely conditional on the performance of the Kabul government. 

A guarantee makes a virtue of a necessity. If it can be used to further reform efforts, that's even better. And ultimately, the guarantee reminds us all that the consequences of war, the burdens and responsibilities it brings, last for decades. These burdens are a good reason to avoid war; but once wars have happened, their results are not so easily undone.

Gerard Russell was in charge of the British government's outreach to the Muslim world from 2001 to 2003. He is now an Afghanistan/Pakistan fellow at the Harvard Kennedy School's Carr Center for Human Rights.