The political party that claimed it would restore “honor and dignity to the White House” has done nothing of the sort. Having on false pretenses led us into the disaster of Iraq, the administration and its supporters are now beginning – cravenly and shamefully – to shift blame onto the Iraqi people. The administration continues to hold hundreds of people without charges in secret prisons around the world, while arguing that torture is O.K. and that President Bush can disregard the laws he doesn’t like. I haven’t even mentioned illegal spying or efforts to keep scientists quiet if they’re saying the wrong thing.

Where’s the honor and dignity?

In her testimony last week before a House panel, Monica Goodling, the Justice Department’s liaison to the White House, admitted that she had “crossed the line” in using political considerations to judge potential Justice Department employees. She may well have broken laws that forbid political influence over civil service positions. But “crossing the line” has been business as usual for the past six years. Goodling’s behavior follows a pattern established across almost all federal agencies, where the administration has sought loyalty over competence at every turn.

Another word for it, of course, is corruption – and it’s natural to wonder how we got so deeply mired in it. If the gathering storm of investigations forces Karl Rove and other White House officials one day to testify under oath, we may have some chance of finding out. And I suspect, if we do, that we’ll discover that honor and dignity were sacrificed at the very top. It will be a familiar story – of a few power-hungry and largely amoral political operatives, the real drivers, whose actions encouraged and directed a small army of fairly ordinary people, the Monica Goodlings of this world, many of whom were hardly aware they were doing something wrong.

People who engage in corrupt acts often do not see them as such. This much has emerged from studies of corporate scandals and fraud at places like Enron or WorldCom. In a study two years ago, for example, business professors Vikas Anand, Blake Ashforth and Mahendra Joshi concluded that most fraud within institutions takes place through the willing cooperation of many otherwise upstanding individuals with no psychological predisposition to be criminals.

Whether embezzling money, undermining product safety regulations, or even selling completely fake products, the perpetrators rationalize away their responsibility. They deny that they actually had any choice, saying that “everyone was doing it.” Or they deny that anyone really got hurt, so there really was no crime: “They’re a big company, they can afford to overpay us.”

Then there’s the popular appeal to higher authority, a mechanism with special relevance, perhaps, to the loyalty-rewarding Bush administration: “I had to do it out of loyalty to my boss.”

All of this isn’t so surprising, actually, when you realize that we like to feel good about ourselves and about those with whom we work, and that our brains have immense talent for producing reasons why we should. People engaged in corruption, the academic researchers suggest, create a kind of psychological atmosphere in which what they’re doing seems normal or even honorable. So if congressional oversight does ultimately expose the machinations behind anything from secret prisons to the United States prosecutor purge, brace yourself for a litany of the usual excuses – “We didn’t know it was wrong” and “We were told to do it.”

But the psychology of rationalization is only part of the story. The other element in all such cases seems to be a chain-like linking together of individual actions that can undermine social norms with surprising speed – or keep them safe, sometimes if just a single person remains strong.

In the late 1970s, Stanford sociologist Mark Granovetter pointed out that the differences among people – in their willingness to engage in certain kinds of acts – can lead to surprises. Think of the dance floor at a party. Some people are more than happy to be the first out there, dancing alone, but lots of the rest of us would like some others out there first. You might be willing to go out if five or six went before you, while others might require 20 or 30. Some might not go out unless everyone at the party was out there.

The point is that each of us has a threshold for joining in, which depends on personality, the music being played and so on, but also – and this is the really important part – on how many others have already joined in. As Granovetter argued, this can make a group’s behavior extremely difficult to predict.

Just imagine, for example, that 100 people at the party have thresholds ranging from 0 to 99. In this case, everyone will soon be dancing, you can be sure of it. The natural extrovert with threshold 0 will kick it off, soon to be joined by the person with threshold 1, and the dancing will grow, eventually involving even the reluctant people.

But notice how delicately the outcome depends on the precise interlocking of these thresholds. If the person with threshold 1 goes home, then after the first person starts dancing the rest will simply stand by watching. With no one willing to be the second person onto the floor, there’s no chain reaction. So just one person can have a dramatic effect on the overall group.

This is just a toy model, but it illustrates something about the logic of people joining not only dance floors, but riots or protests, trips to the pub in the evening, getting in with others to skim cash from the restaurant till – or violating well-known rules against taking political affiliation into account when hiring. Tiny differences in the group makeup, the presence or absence or a few people of the right type, might be the difference between a few renegade violators and division-wide corruption.

I can’t help thinking of the bizarre attempt by then-White House officials Andrew Card and Alberto Gonzales to get then-Attorney General John Ashcroft, drugged and in the hospital, to sign off on a secret National Security Agency wiretapping program. Ashcroft – who back then I would have thought would rubber-stamp anything Bush wanted – was clearly made of sterner stuff and refused, as did Deputy Attorney General James B. Comey. Again, we won’t know how much effect these refusals had – and just how extreme the program was that Bush wanted to authorize – until someone manages to get past White House stonewalling and digs up the real information.

But the fragility of social outcome, its potential sensitivity to the actions of just one person, brings home the profound importance of individual responsibility. Everyone’s actions count. The laws and institutional traditions we have were put in place precisely to help us avoid these social meltdowns, and to give people the incentive not to step over the line, especially when lots of others are doing so already. In particular, the laws of the civil service prevent hiring on the basis of political affiliation (at least for many positions), and the routine violation of those laws puts our democracy at risk. Many people went along with it, and so might have many more, had the creeping corruption not been exposed when it was.

Restoring honesty and dignity. One might say of it what Gandhi said when asked what he thought of Western Civilization: “I think it would be a good idea.”