There are two types of violations of the Sherman Act, the per se violations and the rule of reason violations. A per se violation is one that meets Section 1 of the Sherman Act. Section 1 holds that there was a combination or conspiracy and that this combination or conspiracy had a detrimental impact on interstate commerce (ABA, 2017). There is basically zero chance that Amazon is violating the Sherman Act in a per se manner. First, there has been no combination nor any conspiracy, and furthermore there does not appear to be any damage to interstate commerce. Indeed, the plaintiff literally is still selling its fishing equipment, just doing so through Amazon. Changing channels for retail of a good is not a violation of the Sherman Act, nor is outperforming a competitor operationally. A per se violation actually has nothing to do with the outcomes; the act itself is illegal. There is no evidence of anything close to a per se violation here. The other violation type is the rule of reason violation. This type of violation requires investigation into the outcomes of certain acts. If the outcomes are anticompetitive in nature, then a violation of Section 2 of the Sherman Act...

Section 2 focuses on monopolization, meaning that the company has the intent and the means to monopolize, whether or not it actually does. A good example of this is predatory pricing, where a company prices below cost in order to run competitors out of business, and then subsequently abuses the monopoly position with a sharp price increase to recoup the losses that were incurred in lowering the price in the first place.
I do not think that there are any conditions under which Amazon can be prosecuted. There is zero case for Section 1. There is also zero case for Section 2. It's not even close. To prosecute on Section 2, it would have to the demonstrated that Amazon is selling below cost, and there is no such evidence. Furthermore, there is no evidence that Amazon has monopolized the retail environment. All that has occurred is that the producers of the goods are no longer making money on their bricks-and-mortar stores. Online retail has wiped out a lot of inefficient bricks-and-mortar stores, and that is just competition, not anticompetitive practice. The reality is that only one retail channel is suffering, but there's…