Senate Judiciary Committee Chairman Lindsey Graham, R-S.C., told "Hannity" Thursday that anyone who cares about the "rule of law" should want him get to the bottom of the origins of the FBI's Russia investigation.
"Here's what I can tell you for sure, that the [FISA] court was lied to repeatedly and that the people had a bias against Trump," Graham said. "They acted on that bias and it should never happen again.
"And all I can say, if you care about the rule of law, you should want me to get to the bottom of this."
Last week, former Deputy Attorney General Rod Rosenstein testified that he would not have signed a Foreign Intelligence Surveillance Act warrant renewal application for former Trump campaign aide Carter Page had he known about since-revealed "significant errors" in the application.
Graham told host Sean Hannity that Rosenstein's testimony "tells me that Rosenstein signed a warrant application having no idea what he was signing, that he trusted the system and the system should not have been trusted.
"It tells me that the scope memo in August of 2017 allowing Mueller to investigate the Trump campaign was written by the same people who lied to the court."
Earlier Thursday, the Senate Judiciary Committee voted to give Graham broad authority to subpoena more than 50 people, most of them former Obama administration officials as part of its own investigation into the origins of the Russia probe.
"I'm going to call every person who signed a warrant and ask them, 'Did you know about the doctored email?'" Graham vowed. "'Did you know that the FBI had learned that the dossier was no longer reliable?' And I am sure most of them are going to say 'no.'
"I don't believe McCabe and Comey could have possibly not known that the dossier had been rejected by the sub-source," Graham added. "I can't believe the FBI is that poorly run, that [during] the most important investigation in 30 years of a sitting president that nobody told the top of the FBI, 'Oh, by the way, our case fell apart.'"
"And finally, I'm not gonna let four people who interviewed the sub-source for three months get blamed for this," Graham added. "It's not fair to blame it on the underlings, if in fact, the people at the top knew."
Fox News' Brooke Singman and Chad Pergram contributed to this report.