Apparent discord between Anthem and Cigna appeared to be on display immediately following the government's announcement of its opposition to the mergers. While Anthem vows to fight the suit, Cigna released a statement saying that it was "evaluating its options," and pointedly noted that the merger was "led by Anthem."

In its court arguments in favor of a separate and speedy trial, Anthem highlighted Cigna's apparent willingness to exit the deal. 

"Anthem believes that the merger must close by April 30, 2017, or Cigna will declare that it is terminating the merger agreement the next day," the company says in its filing.

In addition, Anthem has argued that a decision in the next few months will allow it to gain approval from state regulators, many of which have suspended their reviews of the merger as they await the conclusion of the federal legal battle.

In a response filing, the Justice Department, which has asked for a February trial, objected to Anthem's request. Its filing, reported on by the Hartford Courant, seemed almost gleeful in its description of the bickering between Anthem and Cigna.

"Anthem argues it needs a 2016 trial and decision because it is not getting along with Cigna," it says. "The contentious relationship between Anthem and Cigna is certainly relevant to whether combining these two companies will create efficiencies — or more likely — inefficiencies. But whether defendants are getting along (or not) should not cause the court to rush its schedule."

The good news for the company is that the judge that will be hearing the case, U.S. Circuit Court Judge John Bates, has a reputation as being business-friendly. An appointee of President George W. Bush, Bates ruled against a government attempt to block a merger between two major coal companies in 2004.