Mr. Potter (Lionel Barrymore) is one awful guy. Ranked at #6 on the AFI’s list of the greatest cinematic villains in the first 100 years of cinema, he brings a bitter taste to every scene of It’s a Wonderful Life (1946) that contains his character. As the dispirited foil to Jimmy Stewart’s generally caring and pleasant George Bailey, Potter represents the worst qualities of capitalism and greed that live in the callous, elitist minority of wealthy Americans. He preys on the needs of others instead of striving to assist them, culminating in a character that is easy to despise.
Potter’s presence in the film poses an endless nuisance to George Bailey. Potter is the richest person in town, only stopped from even greater riches thanks to the tireless efforts of Bailey and his Building & Loan company. The way Bailey handles his business is based on compassion and community -- a truth that keeps Bailey from ever gaining much material wealth of his own -- but which separates him from the cutthroat money-loving Potter who will do anything to turn a buck. Bailey is happy to sacrifice his own benefits for the benefit of those around him.
When George Bailey’s absent-minded uncle and business partner Billy (Thomas Mitchell) accidentally loses $8,000 cash, the future of Bailey Building & Loan is threatened. With no means of acquiring the funds to keep the business afloat, George Bailey quickly spirals into a depression that has been slowly building his whole life, and considers killing himself -- his $15,000 life insurance policy would take care of the debt and make sure the families in Bedford Falls who rely on his company wouldn’t lose everything. Of course, it’s Potter who has the missing cash. It was accidentally handed to him wrapped in a newspaper. Even when Bailey comes crawling to Potter for a loan, Potter stays silent about his possession and instead takes the opportunity to ridicule and tease Bailey for his poor, charitable business acumen.
This event stumbles George into the dream world where a second-class angel named Clarence (Henry Travers), sent back to Earth to try and earn his wings, shows George how Bedford Falls (now Potterville) would be if he never existed. Once proving all the fruitful ways he has kept the town free of overwhelming Potter tyranny, George realizes his importance and significance. He returns to the real world where the residents of Bedford Falls shower him in their financial generosity, giving back to the man who has given them so much.
But nobody ever finds out Potter stole the $8,000. How did he get away with it? It’s a Wonderful Life was produced in 1946, in the height of the Hays Code which dictated the moral principles on which films had to be founded. One of its commandments was that criminals need to be punished for wrongdoings.
It is arguable that Potter didn’t exactly steal the money, in that he did not consciously make a criminal effort to take the funds from Bailey’s possession. It is a case of moral theft versus legal theft. He found something that didn't belong to him and should have made an effort to return it, but kept it after realizing it could work to his great benefit.
To that end, it is possible that because Potter was hoping the loss of this money would ruin Bailey and his business, the act of his theft was a malicious attempt that didn’t come to fruition. Bailey Building & Loan was able to survive, and therefore Potter’s evil did not prevail.
If It’s a Wonderful Life advocates the common “crime doesn’t pay” mentality of films of the era, we have to attribute a moral sentence to Potter’s behavior. Because George succeeds in the end, the stolen cash becomes somewhat irrelevant. Potter loses because George stays in business. There is an argument to be made that Potter is an amoral character, and therefore a moral punishment for him means little. His life is all about money, and he’s up an easy $8,000 at the end of the situation. But, Potter is also a businessman, and the collapse of Bailey Building & Loan would have resulted in profits of way beyond $8,000 in time. Truly, if that is all he profited from the situation, it is showing that on an implicitly wider scale, crime doesn’t pay.
This must have been the reasoning for the Hays censors allowing Potter to get away with keeping the cash. The viewer is allowed to determine Potter's fate, and few people would explore the character and find him to be an admirable person. It's likely that Potter's overwhelmingly terrible personality and hatred by the community is "code" enough to suggest that people shouldn't behave as he does.