The unprecedented possible move to question Makan Delrahim, who was appointed by President Donald Trump, comes as the companies are making Trump’s public comments disparaging the deal a central facet of their defense. On the campaign trail, Trump vowed that his administration would block the deal and he has repeatedly disparaged Time Warner unit CNN.

AT&T (T) declined to comment to Fortune. Update: On Wednesday evening, AT&T issued a statement. “This is a matter to be discussed in court, not the press, and as we have consistently told all reporters yesterday and today, we will reserve comment on it for the courtroom,” Dan Petrocelli, lead trial counsel for the company, said in the statement.

AT&T and Time Warner (TWX) weren’t expecting Trump’s bluster would translate into actual government opposition to their $109 billion combination (including debt) because they don’t compete with each other. But the Justice Department found that letting AT&T, which has the most pay TV customers in the country, combine with a major supplier of TV programming like Time Warner could still harm competition by potentially shutting out new competitors like Internet TV services.

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Still, opposition to so-called vertical mergers is almost unheard of in recent decades. And before being appointed by Trump, Delrahim gave an interview where he commented more positively about the merger. “The sheer size of it, and the fact that it’s media, I think will get a lot of attention,” Delrahim told the BNN network in Canada. “However, I don’t see this as a major antitrust problem.”

But Delrahim later changed his view and the Justice Department filed suit in November to block the deal. A trial is scheduled to begin on March 19 before U.S. District Judge Richard Leon in Washington, D.C.