A federal judge in Washington blocked Anthem’s proposed $54 billion acquisition of Cigna., handing antitrust enforcers a second win in two months against a major merger in the health insurance sector.

The U.S. Justice Department sued in July to block Anthem’s deal and Aetna’s proposed $37 billion tie-up with Humana, alleging the mergers would amount to an “unprecedented consolidation in the health insurance industry.” In the suit against the Anthem and Cigna merger, federal antitrust lawyers said the deal would hurt competition for millions of consumers who receive health coverage from national employers.

Anthem and Cigna’s defense, at trial, was dogged by tension between the two companies over the execution of the merger. In the buildup to trial, U.S. District Judge Amy Berman Jackson was struck by the feud, at one point remarking that it was a “bizarre situation” to make scheduling accommodations for a deal Cigna appeared to no longer desire.