Senate Judiciary Committee Chairman Lindsey Graham warned the Foreign Intelligence Surveillance Court that it needs to “take corrective action” after being “misled” by the Justice Department and FBI through their use of British ex-spy Christopher Steele’s unverified dossier.

During a radio interview with Sean Hannity on Friday, after it was announced that DOJ Inspector General Michael Horowitz had submitted to Attorney General William Barr a draft of his report on abuse of the Foreign Intelligence Surveillance Act, the South Carolina Republican said his own "deep dive" investigation would include holding the FISA court accountable for its role in allowing the electronic surveillance of onetime Trump campaign adviser Carter Page in 2016 and 2017.

Graham said he would send the results of his committee’s investigation to the FISA court and deliver a message to the judges: “You know it's your court to run, but I've got to be in charge of making sure that Americans' rights are protected.”

“If they don’t take any corrective action, it will prove to me that the court is not reliable,” Graham said. “Because here's what we can prove without any doubt. The court was misled to the accuracy of the Christopher Steele dossier, that the system had plenty of warnings that it was not reliable, it was biased, and they didn't do a damn thing to look into it, and they never informed the court of the bias in any meaningful way.”

The 412 pages of redacted FISA documents released in early 2018 show the DOJ and the FBI made extensive use of Steele’s unverified dossier, which he put together in 2016 at the behest of the opposition research firm Fusion GPS, which was hired by Hillary Clinton's 2016 presidential campaign and the Democratic National Committee by Marc Elias of the Perkins Coie law firm — who was briefed about Steele's findings throughout the race and, in turn, briefed the Clinton campaign too.

Republicans allege Steele’s funding from a Democratic presidential campaign and his desire for President Trump to lose the election were concealed by the DOJ and FBI from the FISA court. The FBI continued to rely on Steele's research even after he was cut off as a confidential human source in November 2016 following the discovery that he had been improperly providing information to journalists, according to notes from interviews with Justice Department official Bruce Ohr.

“If that’s OK with the FISA court, then we need to probably do away with the FISA court,” Graham concluded on Friday.

Earlier this year, Graham told reporters in May he would call up Supreme Court Chief Justice John Roberts and ask him to investigate possible abuse of the FISA court during and after the 2016 election, noting that Trump is "down" on the FISA court.

“Would you please look and see what happened?” Graham said he would ask Roberts. “Because I don’t want to lose the FISA program.”

As the chief justice, Roberts supervises and appoints judges to the FISA court.

The FISA filings required approval from top members of the FBI and the Justice Department, and targets of Horowitz's inquiry likely include the approvers of the four applications and renewals: former FBI Director James Comey; former Deputy Attorney General Sally Yates; Dana Boente, the only signatory in active government service and currently Trump’s top lawyer at the FBI; then-FBI Deputy Director Andrew McCabe; and then-Deputy Attorney General Rod Rosenstein, who appointed former FBI Director Robert Mueller to be special counsel the month before.

The FISA court, for its part, approved all four applications and renewals from October 2016 to June 2017, and the four judges involved were appointed by Republicans. Three of the four judges who signed off on the Carter Page surveillance are still on the FISA court.

“It's my job to make sure our laws work well and the system protects the American people,” Graham said on Friday. “And if I am convinced after all this B.S. and the court doesn’t take corrective action, then I’ve lost faith in the court.”

The initial FISA application was signed in October 2016 by FISA Court Judge Rosemary Collyer, whose signature attested that “on the basis of the facts submitted in the verified application, there is probable cause to believe that the Government of the Russian Federation (Russia) is a foreign power and Carter W. Page is an agent of Russia.”

The FISA warrant authorized the United States government to conduct a wide series of redacted surveillance techniques through January 2017, when the application would need to be renewed. Collyer was appointed to the U.S. District Court for the District of Columbia by President George W. Bush in 2003. Collyer joined the FISA court after being selected by Supreme Court Chief Justice John Roberts in March 2013 and is currently the presiding judge. Her term goes into March 2020.

The second FISA application was signed in January 2017 by Judge Michael Mosman, who was appointed by President George W. Bush as the chief judge of the U.S. District Court for the District of Oregon. Mosman joined the FISA court in May 2013 and will serve on it through May 2020.

The third FISA application was signed in April 2017 by Judge Anne Conway, who was appointed by President George H.W. Bush as the senior judge of the U.S. District Court for the Middle District of Florida. Conway joined the FISA court in May 2016 and will serve on it through May 2023.

The fourth and final FISA application was signed in June 2017 by Judge Raymond Dearie, who was appointed by President Ronald Reagan as a federal judge for the Eastern District of New York. Dearie joined the FISA court in July 2012 and served on it until he left the court in July 2019.