They can offer him immunity. They can bring legal proceeding to determine if his 5th Amd claim is legitimate. There's entire procedures for handling this. And the issue here isn't that "he might lie." It's that the GOP has openly stated they ARE looking to prosecute him and use his testimony
Josh ChafetzIt certainly sounds like Fauci is saying that he thinks Paul is trying to trick him into perjuring himself. But that can't justify invoking the Fifth Amendment, otherwise anyone could get out of testifying anytime by claiming that, if they testified, they might lie. That can't be right.