Greed, we are told by the moral philosophers, brings out the worst in human beings. As Amazon.com is about to prove, the same rule applies to big corporations.

Last week, the giant online retailer announced that it was backing a ballot referendum to overturn a new state law mandating that it collect the sales tax due on purchases by its California customers.

That law, which was signed by Gov. Jerry Brown at the end of June, was designed to eliminate the price advantage enjoyed by Amazon, and many other online retailers, over brick-and-mortar stores. The advantage arises because the latter charge customers sales tax at the register, and Amazon does not — making for a difference of 7.25% to 9.75% of the purchase price, depending on the city and county you're in.