The U.S. Equal Employment Opportunity Commission closed out 2013 with a key win in EEOC v. Mach Mining, persuading an appeals court that the agency’s targets can’t second-guess its prelitigation conduct. Now the EEOC is facing a much bigger test at the U.S. Supreme Court.

The Supreme Court agreed Monday to weigh in on the EEOC’s gender discrimination lawsuit against Mach, an Illinois-based coal mining company. Mach’s lawyers urged the justices to take the case in February, arguing that the EEOC didn’t live up to its unique statutory duty to “conciliate in good faith”—i.e., to try to resolve a dispute fairly before filing suit. The U.S. Court of Appeals for the Seventh Circuit shut down Mach’s line of attack in December, favoring limited judicial review of the EEOC’s conciliation efforts.

According to prominent employment defense lawyer Gerald Maatman Jr. of Seyfarth Shaw, the Seventh Circuit’s ruling has already emboldened the EEOC in its dealings with other defendants in the Midwest. Maatman said the court’s approach to judicial oversight allows the EEOC to be “very aggressive and very difficult to deal with” during settlement talks. The agency can refuse to budge from its demands or even explain them, Maatman said, because it doesn’t have to worry about a judge assessing whether it was sufficiently conciliatory. In other jurisdictions, where the EEOC’s failure to conciliate can be grounds for automatic dismissal, the agency plays it more safe, Maatman said.

“There’s a night and day difference,” Maatman said.

Mach is represented by R. Lance Wichter and David Schenberg of Ogletree, Deakins, Nash, Smoak & Stewart. The company also tapped Thomas Goldstein of Goldstein & Russell to serve as counsel of record at the Supreme Court.

The EEOC didn’t oppose Mach’s cert bid, but its May 27 response makes the agency’s position clear. “As the court of appeals observed, any purported defect in the conciliation process provides no ‘sound basis for dismissing a case on the merits,’” the EEOC wrote. “The remedy for deficiency in process is more process, not letting one party off the hook entirely.” The agency also asserted that it takes seriously its prelitigation obligations as enshrined in Title VII of the Civil Rights Act.

The business community’s response has been skepticism that the EEOC can police itself. In an amicus brief filed by lawyers at Jones Day, the U.S. Chamber of Commerce and other groups provided a long list of cases in which the EEOC has been rebuked in the courts, including a gender discrimination case against Bloomberg LP that a judge found “blatantly” contravened Title VII’s emphasis on resolving disputes without resorting to litigation.

“The Seventh Circuit overlooked this trail of numerous instances of the EEOC’s actual failures to engage in meaningful conciliation,” a Jones Day team led by Eric Dreiband wrote in the brief.