Senate Judiciary Lindsay Graham (R-S.C.) responded to President Trump's tweet calling for Graham to compel former President Obama to testify before Congress about the Russia investigation, telling Politico: “I don’t think now’s the time for me to do that. I don’t know if that’s even possible.”

What's happening: Trump has tweeted hundreds of times about "Obamagate" — the baseless claim that the Russia investigation was a political hit job ordered by Obama — following the Justice Department's decision to drop its case against former national security adviser Michael Flynn.

Trump tweeted on 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 @LindseyGrahamSC, just do it. No more Mr. Nice Guy. No more talk!"
Graham told Politico: “I understand President Trump’s frustration, but be careful what you wish for.”
Between the lines: Trump's own Department of Justice published an opinion last year — following its decision to block former White House counsel Don McGahn from complying with a subpoena — that argued that former presidents can't be forced to testify before Congress.