Cohen Milstein Sellers & Toll lost an early round Monday in a spat with Hausfeld and another plaintiffs firm over who should lead part of a sprawling antitrust litigation over alleged manipulation of foreign exchange rates. But the dispute isn’t fully resolved, and judging by a snippy letter Cohen Milstein filed last week in Manhattan federal court, there could be plenty of acrimony ahead.

In a letter Friday to U.S. District Judge Lorna Schofield in Manhattan, Cohen Milstein accused lawyers at Hausfeld and Scott + Scott of engaging in deception on par with that of former President Richard Nixon. The letter came as Schofield considers Hausfeld’s and Scott + Scott’s motion to serve as co-lead plaintiffs counsel in one piece of the putative class action, which accuses a dozen banks of widespread misconduct in the $5 trillion-per-day foreign exchange market.