Sen. Richard Burr has become a believer.

The Republican chairman of the Senate Intelligence Committee—who endorsed Trump, voted for Trump and served on Trump’s national security advisory council during the campaign—will preside Thursday over the first open hearings on Russian “active measures” against its adversaries. In stark contrast to their House counterparts, Burr holds the unflinching faith of Democratic Vice Chairman, Sen. Mark Warner. The two men stood together Wednesday afternoon at the front of a packed, sweaty Capitol press gallery.

“I have confidence in Richard Burr, that we, together with the members of the committee, are going to get to the bottom of this,” Warner said. “If you get nothing else from today, take that statement to the bank.”

Following the president’s election in November, lawmakers jockeyed for position as various committees sought to lead investigations into Russian interference with the U.S. election process. The responsibility for the Senate’s main probe was ultimately handed to Burr’s panel, but it was not always clear how far Burr was willing to investigate.

In fact, after Trump’s election, he told reporters he didn’t believe his panel should be probing links between Trump’s campaign and the Kremlin. “That’s not our role,” he told reporters on Jan. 12.

By the next day, Burr had changed his mind after Democrats on the committee threatened to boycott the investigation if Trump team ties wasn’t included, according to Politico.

On Jan. 13, the Senate Intelligence Committee issued a bipartisan statement outlining the scope of their probe: the extent of Russian interference in the 2016 campaign; a review of the intelligence community’s assessment that Russia tried to disrupt the election; and links between Russia and U.S. political campaigns, including Trump’s.

“This one is one of the biggest investigations that the Hill has seen in my tenure here,” Burr told reporters Wednesday.

Burr’s commitment to an inquiry that involves the sitting president from his own party hasn’t waned since, a signal to Democrats that they can trust his integrity and independence.

“Warner and the Dems have been saying from the beginning they wanted this to be part of it. Burr told the press no [on investigating the Trump campaign], but 24 hours later they were able to secure an agreement,” a senior Senate aide told The Daily Beast. “Since that agreement was reached, the investigation has moved forward and is progressively into looking into it. There’s a united front among committee members on that.”

That’s in stark contrast to the House’s probe, where Intelligence Committee Chairman Devin Nunes briefed the president about mysterious secret documents before he briefed his own committee and has since suspended all planned hearings.

Asked Wednesday whether he had coordinated at all with the White House regarding what the committee would investigate, Burr responded, “No, sir, I have not,” adding that “the relationship and trust” between the Democratic and Republican members of the committee would keep it from going off track.

“I think it’s not only our relationship, but it’s the fact that the committee I think has got our back and they want to see it through,” Warner said. He added that if the White House were to try to interfere with their investigation, “you’ll hear from us.”

The two had a buddy-buddy act throughout the press conference on Wednesday. When a reporter prefaced a question with, “ I ask this with no disrespect,” Burr quipped, “[Warner] disrespects me all the time.”

At another point, pleased with a response from his counterpart’s, Warner looked over and smiled, telling Burr, “good answer.” Referring to the dysfunction in the House Intelligence Committee, a reporter asked whether there would ever be a circumstance where Burr would hide one of his sources from Warner, Burr joked, “he usually knows my sources before I do.”

The committee has has been provided an “unprecedented amount of documents” by the intelligence community, said Burr, “thousands of raw intelligence and analytic products,” the majority of which have already been reviewed by the seven professional staff members devoted to the probe.

This week, the Senate Intelligence Committee began to schedule its first interviews. It has sought to interview 20 individuals, and arrangements for five have been finalized. They begin as early as next Monday.

And on Thursday, the Senate Intelligence committee will hold an open hearing featuring Russia experts and former NSA Director Keith Alexander.

“When we started this, we saw the scope and what was involved. I said it was the most important thing I’d ever taken on in my public life. I believe that more firmly now than even when we started. We’re gonna get it right,” Warner pledged.