Sen. Richard Shelby (R-AL), the longtime retiring senator from Alabama, plans to oppose former President Donald Trump in the primary to replace him and attack Trump’s pick for the nomination, Rep. Mo Brooks (R-AL), Breitbart News has learned.

Shelby will, in a yet-to-be-published interview with National Journal, attack Brooks as “irrational.”

“A lot of people would think so. Look at his record,” Shelby told National Journal’s Matt Holt when asked if Brooks would be an “irrational senator,” a transcript of their conversation provided to Breitbart News shows.

Shelby also told National Journal he will “absolutely” be helping his former chief of staff Katie Britt—dubbed the “Alabama Liz Cheney” given her work for swamp consultancies—“everywhere I can.”

“I mean, she has to run her own race, I don’t run people’s race. She’s highly qualified, and a very rational person,” Shelby said. While Shelby claims she is “qualified” to be a senator, Trump made clear she is not “qualified to be a senator” in a recent July 10 statement about Britt.

Trump said on July 10, shattering the idea that Britt is a credible or qualified candidate for Senate:

I see that the RINO Senator from Alabama, close friend of Old Crow Mitch McConnell, Richard Shelby, is pushing hard to have his ‘assistant’ fight the great Mo Brooks for his Senate seat. She is not in any way qualified and is certainly not what our Country needs or not what Alabama wants. For Mitch McConnell to be wasting money on her campaign is absolutely outrageous. Vote for Mo Brooks! He stands for America First, and everything Alabama wants. He also has my Complete and Total Endorsement.

Shelby, in his comments to National Journal that are not yet published, was asked about Trump’s statement and said he thinks Brooks is “calling on the president” to do that.

“I think Mo Brooks’s camp is probably calling on the president,” Shelby said. “I don’t know this. He feels the momentum that Katie’s really just getting started, they’re showing a lot of interest, and they’re probably nervous about it.”

Brooks, who has been a stalwart conservative and clearly has Trump’s full support in Alabama, provided the transcript of what National Journal’s Holt gave him to Breitbart News along with a lengthy statement responding to Shelby.

“I get that Richard Shelby wants to bequeath Alabama’s Senate seat to his former, relatively inexperienced employee,” Brooks said in the statement in response. “But U.S. Senate seats should never be inherited or bought, they should be earned and decided by the people of Alabama. In any event, ‘rationality’ and ‘irrationality’ are in the eye of the beholder.  I am 100% certain that, to Washington’s Swamp and special interest groups who routinely buy Congressmen and Senators, I appear very irrational because I put America First and special interest groups and their Swamp money dead last! No person in Alabama history has been elected more times to public office as a Republican than has Mo Brooks. As such, I respectfully submit that Alabama voters have a much different perception of rationality than do Washington’s Swamp critters.”

Brooks in his statement continued by noting that Shelby withdrew his support—something Britt also did—for the GOP ticket for U.S. Senate in the 2017 special election, which led to the Democrats getting the seat in Alabama for some time and halting much of the conservative agenda President Trump sought to champion.

“I considered it rational in 2017 to support the Republican nominee for the U.S. Senate over Socialist Democrat Doug Jones because President Trump and the GOP badly needed that one Senate vote to successfully gut ObamaCare in 2018 (after John McCain was replaced by Martha McSally),” Brooks said. “Katie Britt & Richard Shelby had the right to help Doug Jones win and protect ObamaCare. I respectfully disagree. I consider it rational to minimize America’s debt and risk of suffering a dangerous and debilitating national insolvency and bankruptcy.  Katie Britt & Richard Shelby have the right to burden America with $30 trillion in debt.  I respectfully disagree. On January 6, I considered it rational to join ALL six other Alabama Republican Congressmen and Senators in voting with President Donald Trump and against the electoral college vote submittals of Arizona and Pennsylvania.  Richard Shelby had the right to be, and was, the only Alabama Republican to vote with Joe Biden. I respectfully disagree.”