Antitrust law and economics seem like dark arts to outsiders, an impression that antitrust lawyers are none too eager to dispel. But everyone can appreciate a smoking gun document that seems to brand its author as a hardened violator of the antitrust laws. Consider the memorandum written by a large waste-disposal company about a small rival, quoted by the Supreme Court in 1989: “Put [him] out of business. Do whatever it takes. Squish him like a bug.”

Seemingly inculpatory documents, however, have different significances in different contexts. Sometimes, a document vividly expressing anticompetitive ambitions can be the linchpin of an antitrust case. In other situations, however, those documents have little significance, or even help a defendant ward off an antitrust claim.

The Department of Justice recently relied almost entirely on damning internal documents in its challenge to the acquisition of a small rival by the leading producer of online product ratings and reviews platforms for retailers. Top managers of the acquirer wrote that the deal would “[e]liminat[e] [our] primary competitor” and provide “relief from price erosion,” “tak[e] out [our] only competitor” who was “suppress[ing] [our] price points,” and “avoid margin erosion” caused by “tactical ‘knife-fighting’ over competitive deals.”

In merger cases, such documents may be particularly credible. They express the acquirer’s frank view of the markets in which it operates, and often are intended to be relied on by the company’s top management and its board of directors in making a major investment.

Sometimes, however, merger-related hot documents can’t be taken at face value. Deals often have internal cheerleaders who overstate an acquisition’s competitive benefits, and whose views aren’t necessarily shared by top decision makers. Sellers—often represented by eager investment bankers—can exaggerate entry barriers and overstate the competitive significance of the company being sold.

In monopolization or attempted monopolization cases, expressions of hostility toward rivals are often ambiguous. The intent to annihilate one’s competitors by selling superior products at low (but non-predatory) prices is simply the intent to compete, no matter how ferociously those sentiments may be declared. Businesses don’t sign admissions of antitrust liability when they proudly describe themselves as “competition killers.” When one competitor told another, “We are going to run you out of the . . . business. Your days are numbered[,]” the Seventh Circuit dismissed the threat as irrelevant: “Firms ‘intend’ to do all the business they can, to crush their rivals if they can. ‘Intent to harm’ without more offers too vague a standard in a world where executives may think no further than ‘Let’s get more business.’”

Finally, in price-fixing or market division cases, expressions of chumminess toward competitors help prove anticompetitive collusion. For example, an executive of a corn syrup producer alleged to have fixed prices wrote that “our competitors are our friends. Our customers are the enemy[,]” a statement that the Seventh Circuit observed “will win no friends for capitalism.” How much better would it have been for that executive and his company if he had said that competitors were to be “squished like bugs,” not befriended.