On Thursday, the Federal Communications Commission announced that it would be charging ahead with a vote to formally approve the T-Mobile-Sprint merger; but Democratic senators are calling on the agency to reopen the issue for public comment before taking that vote.

Senator and 2020 presidential candidate Amy Klobuchar (D-MN) penned a letter along with others like Cory Booker (D-NJ), Kirsten Gillibrand (D-NY), and Elizabeth Warren (D-MA) asking the FCC to receive feedback from citizens and advocates on the $26 billion telecom merger one last time before approving it, citing concerns that the deal will only entrench telecom monopolies.

“We have major antitrust concerns regarding the impact of the proposed T-Mobile/Sprint merger”

“We have major antitrust concerns regarding the impact of the proposed T-Mobile/Sprint merger on consumers, competition, and the public interest,” the senators wrote. “We remain concerned about the lack of transparency in the FCC’s merger review process and the lack of certainty on whether this merger will protect competition and consumers.”

There have been a number of public commenting cycles that considered the merger already, but these all occurred before the Justice Department worked out a deal with T-Mobile-Sprint to hand off some of its assets, like Boost Mobile, to Dish Network. With these handoffs, Dish would supposedly be able to build out a fourth major wireless carrier to replace the loss of Sprint. Critics, like Klobuchar, are afraid that this may not be the case, and in approving the deal, both the DOJ and FCC would stifle competition instead.

“This transaction has been pending in front of the Commission for more than a year, and there have been multiple public comment cycles,” an FCC spokesperson told The Verge. “Moreover, the commitments offered by T-Mobile and Sprint to the Commission have been public since May, and many parties have submitted comments about them.”

“The time has come for Commissioners to vote and for this proceeding to be brought to a close,” the spokesperson continued.

In May, FCC Chairman Ajit Pai said that he would vote to the approve the merger after the carriers made promises to the agency that, if approved, they would work to more quickly deploy 5G across the country and in rural areas. The two other Republican commissioners, Brendan Carr and Mike O’Rielly, also said they would vote to approve, basically ensuring that the merger would receive the go-ahead to close.

On Thursday, the chair of the House Judiciary subcommittee on antitrust Rep. David Cicilline (D-RI) also wrote to Pai asking for the agency to take more time to review the deal.

“As I have noted before, the proposed transaction is presumptively illegal under decades of black letter law and the Justice Department’s merger enforcement guidelines,” Cicilline wrote.

Outside of these calls from Congress, the T-Mobile-Sprint deal also faces a multi-state lawsuit led by New York AG Letitia James and California AG Xavier Becerra. When the Justice Department said it would approve the deal last month, a few states dropped the lawsuit, including Nebraska and Kansas. But over the past few weeks, others have hopped on in support like Texas and Oregon. The trial is set to begin on December 9th.