Ever since President Donald Trump took office, chatter has swirled around whether his Justice Department will continue to pursue breaking up Live Nation and Ticketmaster. It’s an open question, and there are signals both ways.

Trump’s inner circle has voiced support for the previous administration’s antitrust crackdown, with Vice President J.D. Vance openly praising the work of the Federal Trade Commission under Lina Khan, and merger enforcers haven’t abandoned their bids to split giant tech companies. On the other side, it appears that the Justice Department won’t sue to block Capital One’s proposed acquisition of Discover Financial Services, which was initially met by concerns that the deal poses competition issues.

Now, advocates and lawmakers are stepping in.

The American Economic Liberties Project, a nonprofit supporting more aggressive antitrust enforcement, and the Break Up Ticketmaster Coalition urged the Justice Department on Thursday to proceed with...