A half dozen Democratic senators led by Amy Klobuchar (Minn.) and Richard Blumenthal (Conn.) and including at least three presidential candidates, are grilling the Justice Department about possible White House interference into the antitrust review of the proposed merger of T-Mobile and Sprint.

Related: Dems Seek Public Comment on T-Mobile-Sprint Conditions

That came in a letter to antitrust chief Makan Delrahim and following a report that while career Justice staffers had recommended denying the deal--which would combine the number three and four wireless carriers--the White House had signaled it liked the deal.

“Since the beginning of this Administration, we have repeatedly raised concerns about reported White House attempts to interfere with the Department of Justice’s antitrust enforcement decision making,” they wrote. “In light of the potential implications of this transaction for American consumers, we write to reiterate that the Department’s decisions should be based on an impartial analysis of the facts and the law, and must be entirely free of improper political influence.”

"This is not the first time that reports have suggested that the White House may have attempted to improperly influence the Department of Justice’s merger review process. Some of us raised similar concerns regarding reports that President Trump ordered Gary Cohn, then the Director of the National Economic Council, to pressure the Antitrust Division to block the AT&T-Time Warner merger."

They want "any and all communications between the White House and Department related to the T-Mobile-Sprint merger."

Also signing on to the letter were senators Tom Udall (D-N.M.), Edward Markey (D-Mass.), Elizabeth Warren (D-Mass.), and Cory Booker (D-N.J.).

For her part, Warren has not been shy to telegraph what her administration would do in terms of communications companies, something Trump was criticized by Democrats for doing. Warren has said that if she were elected, her Justice Department would break up. "I will appoint regulators who are committed to using existing tools to unwind anti-competitive mergers, including: Amazon: Whole Foods; Zappos; Facebook: WhatsApp; Instagram; and Google: Waze; Nest; DoubleClick," she said.

Perhaps lighting a fire under the Democrats is the fact that last week the FCC's Republican majority has signaled it will support the Sprint/T-Mobile deal after chairman Ajit Pai said he would circulate an order approving it after the companies volunteered a revised list of conditions that included divesting Boost Mobile, the low-cost prepaid wireless subsidiary; building out high-speed 5G wireless service to most of the nation, including rural areas, on a timetable acceptable to the FCC; and maintaining the same or better prices for three years."

The FCC majority apparently views creating a stronger competitor to AT&T and Verizon and advancing the Administration priority of 5G is enough to get it over the four-to-three antitrust issue with consolidation in the wireless market.