Update: Warren's office, which has declined to comment on the record, now says the senator is now scheduled to meet with Delrahim.

Massachusetts Sen. Elizabeth Warren is blocking the confirmation of President Trump's nominee to run the Justice Department's antitrust division, offering no explanation and refusing an offer to meet with Makan Delrahim, according to a source with knowledge of the confirmation process.

Warren reportedly put a "hold" on Delrahim's nomination as the Senate confirmed dozens of nominees for key administration positions before lawmakers started their August recess. Warren's obstruction came after Delrahim's nomination sailed through the Senate Judiciary Committee by a 19-1 vote featuring broad support from some of the Democratic Party's most liberal members.

A source with knowledge of the process to confirm Delrahim told the Washington Examiner that Warren has not responded to a request to meet Delrahim.

Warren's office declined to comment to the Washington Examiner, but clues about her opposition can be found on her Facebook page and in her potential 2020 presidential aspirations. Warren commented on Delrahim's nomination in an April post saying that by picking Delrahim, "Trump shows that he'll put the interests of giant corporations ahead of the American people."

Delaying Delrahim's nomination could serve to prevent him from becoming involved in the potential AT&T-Time Warner merger that Warren has urged the Justice Department to reject. As a presidential candidate, Trump in October identified the deal as "an example of the power structure I'm fighting," but in January, shortly before his inauguration, he acknowledged that "I haven't seen any of the facts yet" about the merger.

Delrahim, a deputy White House counsel in the Trump administration, has not said how he would approach the deal. Delrahim declined to comment to the Washington Examiner.

Warren stands apart from like-minded liberal senators and those with potential 2020 aspirations, such as Minnesota Sens. Al Franken and Amy Klobuchar, who voted to advance Delrahim's nomination out of the Judiciary Committee.

Carrie Severino, chief counsel of the Judicial Crisis Network that has boosted Trump's nominees to the judiciary, told the Washington Examiner that neither Franken nor Klobuchar appears to be running for president as actively as Warren is.

"This is not someone who there's any principled reason to oppose," Severino said of Delrahim's nomination. "I think this is really part of a pattern of [Democratic] obstruction that we've seen that's been most stark when you look at some of these administration appointments. It's shameful the length of time it took to get everyone from the Cabinet on down confirmed."

Behind the scenes, Delrahim's GOP allies in the Senate are working to ensure his confirmation when it comes up for an expected September vote. Utah Sen. Orrin Hatch, a longtime Senate Judiciary Committee member, is lobbying Minority Leader Chuck Schumer and others in Democratic leadership on Delrahim's nomination.

In a statement to the Washington Examiner, Hatch spotlighted comments from the Judiciary Committee's top Democrat about Delrahim.

"I agree with Senator [Dianne] Feinstein that he will ‘fully and fairly enforce our antitrust laws,'" Hatch said. "The ongoing attempt to block his confirmation is purely political and does nothing to help American businesses and consumers."