Ruhle hosted a panel discussion about why Graham has pivoted from being a past critic of Trump to one of the president’s biggest allies in the Senate.
“It could be that Donald Trump or somebody knows something pretty extreme about Lindsey Graham,” Ruhle said before quickly ending the segment. "We're gonna leave it there."
Perhaps the outspoken MSNBC host is simply a big fan of comic book movies.
On Sunday, Graham tweeted that Trump should declare a national emergency to build a southern border wall when “Captain America” actor Chris Evans openly pondered, “What do they have on you?”
Ruhle did not elaborate on her theory that Graham is being blackmailed by Trump or a member of his administration. Before the MSNBC host voiced her unproven theory, guest David Jolly pointed out that Graham called Trump a "racist, xenophobic bigot” before he was elected.
“I doubt Lindsey Graham could tell you Donald Trump had a change of heart in the last 24 months, I bet the change of heart has been with Lindsey Graham, not the president,” Jolly said.
Graham – who emerged as a hero in conservative circles during the Supreme Court nominee Brett Kavanaugh confirmation hearing -- has been friendly to the White House on most issues, but last month criticized the president’s decision to withdraw U.S. troops from Syria.
Last week, Graham was elected Wednesday to serve as Senate Judiciary Committee chairman.