Think of it this way: When you're teaching a kid to ride a bicycle, you've got to hold onto the bike to help him balance. But once he's learned how, holding onto the bike only causes problems. So it is with nations.
It turns out that social scientists have a pretty good sense of when states should let go. Almost 50 years ago, the revered sociologist Seymour Martin Lipset observed that the "more well-to-do a nation, the greater the chance it will sustain democracy."
More recently Adam Przeworski of New York University confirmed this truism by studying every attempted transition to democracy around the globe. He and his colleagues found that once a country passes $6,000 in per capita income it is virtually guaranteed to succeed in its transition to democracy. States between $3,000 and $6,000 have less than a 50-50 chance of staying democracies. And countries below $3,000 are almost bound to fail.
Why is this? The short answer is that liberty tends to come with a thriving middle class, which needs or demands stuff like relatively uncorrupt courts and bureaucracies, unions, enforceable contracts and property rights, healthcare and access to education, particularly for women.
The one great exception are nations with huge amounts of oil or other natural resources. As Fareed Zakaria notes in his wonderful book, "The Future of Freedom," these states didn't "earn" their wealth and so they didn't develop the liberal habits and institutions necessary to sustain a democracy.
If this all sounds vaguely like a "root causes" argument - i.e. poverty and poor education cause terrorism, dictatorships and tooth decay - I confess it is. But the conventional root-causers should know that foreign aid doesn't help, it hurts. Yes, it prevents starvation, and that's good. But studies show that foreign aid prevents the sort of development that leads to democracy, almost as much as oil wealth does.
Unfortunately, Iraq's per capita income is only between $1,500 and $2,400, and at least some of that comes from oil wealth - though Saddam's regime was sufficiently greedy that much of it was probably earned.
Regardless, if America were serious and free to do this the right way, we would do what we did in Japan. We'd start from scratch and build the institutions necessary for long-term success.
Instead, we'll get a lot of lever-pulling early. Unfortunately, that won't signal that it's time to celebrate.