FIRST ON FOX: Rep. Ronny Jackson, R-Texas, the White House physician-turned-House lawmaker, is demanding in a new letter that President Biden submit to a drug test before his Thursday "CNN Presidential Debate" with former President Trump.
Jackson made his request for a "clinically validated drug test" in a three-page message to Biden and his physician, Dr. Kevin O’Connor.
"This drug test should be administered both immediately before and after the debate and should include, but not be limited to, performance enhancing drugs," Jackson wrote.
He said debates "have given the American public the opportunity to gain critical insight into specific policy positions held by individual candidates, to demonstrate each candidate's leadership qualities and style, and to observe the candidates' ability to perform in an unscripted and high-pressure environment."
"American citizens must have absolute confidence in their President's ability to perform his or her duties as Head of State and Commander in Chief, and the debate performance absolutely should be indicative of an individual's ability to perform these critical duties free of any performance enhancing drugs or mood-altering medications," the letter said.
He pointed to a recent Wall Street Journal report that cited interviews with more than 40 people to paint a picture of an 81-year-old leader losing his sharpness even as problems both at home and abroad grow more complex.
Biden and his Democratic allies furiously pushed back on that report, calling it a GOP hit piece.
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Jackson also brought up special counsel Robert Hur’s interview with Biden regarding his handling of classified documents, when Hur said a jury could see the president as a "a sympathetic, well-meaning, elderly man with a poor memory."
He then accused Biden of using performance-enhancing drugs during the State of the Union, describing the president as having been "profusely sweating, yelling at the camera, not blinking, and frequently moving and gesturing with his hands at a rapid rate."
There have been several recent polls that show Biden's age is a top concern for voters.
A March New York Times/Siena College poll found that 61% of respondents who voted for Biden in 2020 agreed with the statement, "Joe Biden is just too old to be an effective president."
"President Biden, throughout your presidency, over one hundred Members of Congress have called on you on five separate occasions to submit to a cognitive exam, however each of those requests have been ignored by you and your physician Dr. O'Connor," Jackson wrote. "President Donald J. Trump set a precedent during his presidency to document and demonstrate the sound mental abilities necessary to fulfill the duties of the Office of the President."
"Unfortunately, President Biden, your refusal to submit to a cognitive exam, and Dr. O'Connor, your unwillingness to address the American people regarding the President's true mental and physical fitness for duty, has created a condition of great concern for our country as Americans watch the continued decline in our president's cognitive performance."
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Before being elected to the House of Representatives, Jackson served as White House physician under both Trump and former President Obama.
Jackson is a vocal supporter of Trump and was one of the first House Republicans to endorse the former president's 2024 presidential bid.
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When asked if he believes Trump should also undergo the same drug testing before the "CNN Presidential Debate," Jackson's spokesperson told Fox News Digital, "This is a Biden specific concern based on the unexplained change in his demeanor during the [State of the Union]. President Trump has been the same his entire life, and there have definitely been no concerning changes. President Trump has also previously offered to take one if Biden does."
White House spokesman Andrew Bates responded to Jackson's comments by comparing him to a character from "The Simpsons" who is known to have questionable medical practices.