(This must be contrasted with rule of reason analysis.) Conduct considered per se unlawful includes horizontal price-fixing, horizontal market division, and concerted refusals to deal. Violations of the "rule of reason": A totality of the circumstances test, asking whether the challenged practice promotes or suppresses market competition. Unlike with per se violations, intent and motive are relevant when predicting future consequences. The rule of reason is said to be the "traditional framework of analysis" to determine whether Section 1 is violated. The court analyzes "facts peculiar to the business, the history of the restraining, and the reasons why it was imposed," to determine the effect on competition in the relevant product market. A restraint violates Section 1 if it unreasonably restrains trade. Quick-look: A "quick look" analysis under the rule of reason may be used when "an observer with even a rudimentary understanding of economics could conclude that the arrangements in question would have an anticompetitive effect on customers and markets," yet the violation is also not one considered illegal per se. Taking a "quick look," economic harm is presumed from the questionable nature of the conduct, and the burden is shifted to the defendant to prove harmlessness or justification. The quick-look became a popular way of disposing of cases where the conduct was in a grey area between illegality "per se" and demonstrable harmfulness under the "rule of reason". Modern trends Inference of conspiracy A modern trend has increased difficulty for antitrust plaintiffs as courts have come to hold plaintiffs to increasing burdens of pleading. Under older Section 1 precedent, it was not settled how much evidence was required to show a conspiracy. For example, a conspiracy could be inferred based on parallel conduct, etc. That is, plaintiffs were only required to show that a conspiracy was conceivable. Since the 1970s, however, courts have held plaintiffs to higher standards, giving antitrust defendants an opportunity to resolve cases in their favor before significant discovery under FRCP 12(b)(6). That is, to overcome a motion to dismiss, plaintiffs, under Bell Atlantic Corp. v. Twombly, must plead facts consistent with FRCP 8(a) sufficient to show that a conspiracy is plausible (and not merely conceivable or possible). This protects defendants from bearing the costs of antitrust "fishing expeditions"; however it deprives plaintiffs of perhaps their only tool to acquire evidence (discovery). Manipulation of market Second, courts have employed more sophisticated and principled definitions of