Sen. Lindsey Graham (R-SC) had some legal advice for the president’s son on Sunday morning: ignore my colleagues’ subpoena.

Graham suggested in an appearance on Fox Business that the subpoena is related to testimony that Michael Cohen gave surrounding the Trump Tower meeting in June 2016 and the pursuit of a Trump Tower in Moscow. Graham referred to Cohen as a “worthless” witness, but said he understood Sen. Richard Burr’s (R-NC) bipartisan motivation for the subpoena.

“If I were Donald Trump Jr.’s lawyer, I would tell him, you don’t need to go back into this environment anymore,” Graham said. “You’ve been there for hours and hours and nothing being alleged here changes the outcome of the Mueller investigation. … I would call it a day.”

The Senate Intelligence Committee subpoenaed Donald Trump Jr. recently to compel him to testify before lawmakers in light of the findings in special counsel Robert Mueller’s report.