'Next time ask a grown-up': Republican senator blasted for easily disproven 9/11 falsehood
Sen. James Lankford (R-OK). (Photo by Drew Angerer/Getty Images)

A Republican senator Friday was skewered for sharing a 9/11 falsehood in a failed attempt to push strict border measures.

The X message from Sen. James Lankford (R-OK) about closing the southern border earned a “readers added context” message with links to multiple official sites disproving his claim.

“All of the 9/11 attackers were present in the US illegally,” wrote Lankford. “We shouldn’t wait until the next horrific terror attack to realize that our wide-open southern border is a national security risk.”

ALSO READ: Trump goes silent on ‘serious voter fraud’ after long trashing New Hampshire as ‘rigged’

As was later shown in a House Homeland Security committee hearing, the 9/11 Commission Report and a committee report delivered to the U.S. Senate, the 19 terrorists entered the U.S. with visas obtained over a course of years.

Keith Olbermann put it more bluntly.

“You are completely wrong about this. They were all here legally,” he replied. “Next time ask a grown-up first.”

Retired CIA member John Sipher chastised Lankford for his lack of research.

“Come on,” Sipher said. “You have access to the truth.”

Lankford published his X post shortly before noon and had not responded to comments or retracted the tweet by 6:30 P.M. Eastern Friday.

The timing was not ideal.

The Republican senator is at the center of a contentious battle between the far right and Democrats to tighten the southern border with bipartisan legislation.

Lankford, tasked by Sen. Mitch McConnell with negotiating the deal, now faces mounting criticism from the far right as he tries to push the yet-to-be-released legislation forward. His defense has been to accuse critics of spreading misinformation.

“There’s a lot of misinformation out there right now,” Lankford said in an interview with CBS on Sunday. “There’s just a lot of internet rumors that are running around.”