Problem is that the burden of proof to prove that they don’t actually believe their testimony is basically impossible. You’d practically need a direct quote saying they intended to lie for their testimony. Even quotes of them saying the exact opposite before and after the trial, can easily be defended by simply saying “I changed my mind. My testimony was what I believed at the time”
He sure didn’t have an issue in 2015 and beyond when Trump was targeting the brown immigrants. Fuck you Mitch