Sen. Lindsey Graham (R-South Carolina), chairman of the Senate Judiciary Committee, made it clear on Friday that he doesn’t plan to call the former President Barrack Obama to testify about the Russian investigation.

“I am greatly concerned about the precedent that would be set by calling a former president for oversight,” Graham said in a statement. “No president is above the law.”

The statement came following Trump’s tweet earlier Thursday.

“If I were a Senator or Congressman, the first person I would call to testify about the biggest political crime and scandal in the history of the USA, by FAR, is former President Obama. He knew EVERYTHING. Do it Lindsey Graham, just do it. No more Mr. Nice Guy. No more talk!” Trump wrote.

Graham also reiterated his stance to Politico in an interview on the same day.

“I’m very, very sensitive to the separation of powers, the executive branch — we do have oversight of it as Congress, appropriate oversight,” Graham said. “But hauling a former president before an oversight committee, I don’t think that’s been done before. And, presidentially, I’d be careful what I wish for.”