The Iraqi elections, imperfect as they were, convinced some American leaders that the Iraqi people had reached a point of no return -- quite literally turning a corner in the direction of democracy.
"That has to cause a tipping of support for the government, whoever's elected, because of the confidence that all of those people have to feel as a result of seeing so many others of the same view," Secretary of Defense Donald Rumsfeld said.
But the continuing chaos in parts of Iraq has others worried that the country could still tip either way -- toward democracy or disintegration.
That very notion that specific events, violent or peaceful, can tip a neighborhood -- or an entire nation -- is at the very heart of Malcolm Gladwell's influential best seller, "The Tipping Point."
The author cites the example of a bottle of ketchup. Tap the bottle a few times and a few dribbles of ketchup come out. But at some precise point, the tipping point, those dribbles turn into a steady stream.
Many years from now, when the outcome has been settled, historians may focus with blinding clarity on a particular moment or event and proclaim that is when the outcome of the war in Iraq was sealed.
If Iraq evolves into a thriving democracy, people might point to January's elections as the crucial breakthrough event. If the country breaks up in a bloody civil war, Washington's dissolution of the Iraqi army in the spring of 2003 may be identified as the critical mistake.
It takes time.
For example, it was seven years after the North Vietnamese launched their Tet offensive in January 1968 before the last American troops finally left Vietnam. Militarily, the North Vietnamese may have won nothing in 1968, but they did achieve a huge psychological victory by driving into the heart of Saigon and onto the very grounds of the U.S. Embassy. It's fair to say 1968 was the beginning of the end.
D-Day in June 1944 was clearly a major tipping point in World War II, despite the fact that the killing and the devastation ground on for almost another year before the Germans surrendered.
Often, though, the course of events is affected by very small changes. This idea of a tipping point comes from the study of epidemic disease.
"You could have one or two cases of colds in a class of youngsters, but they each might get better," said Mark Rosenberg, an epidemiologist. "But if you had seven or eight youngsters who are sick, then they might transmit it to the other people in the class. And when you had seven or eight sick with colds, there might be no effective way to prevent it from spreading. So, the tipping point is somewhere between two and seven or eight youngsters, when they become infected."
The question, by no means settled, is whether theories about the spread of germs in a classroom, for example, can also be applied to patterns of human behavior, including violence.
Los Angeles Police Chief William Bratton is a believer. In the 1990s, when he led New York's police department, officers aggressively targeted even minor crimes, such as avoiding fares on the subway. In less than three years, violent crime rates dropped by double digits. In New York's most murderous precinct, known as "the Killing Fields," homicides fell by nearly two-thirds.
The reason, Bratton said, is because police had attacked the tipping points that had led to a crime epidemic.