Donald Trump assassination suspect Ryan Routh, who is accused of attempting to shoot the president last year at one of his golf courses, has been blocked from accessing “classified information” related to his criminal case, with a federal judge ruling its disclosure out of the question Friday for “national security” reasons.

“Its disclosure could cause serious damage or exceptionally grave damages,” wrote U.S. District Judge Aileen Cannon in a two-page ruling, where she granted the government a protective order to keep the info at issue under wraps.

Filed earlier this year and argued behind closed doors, the Justice Department made the ask in a sealed motion and at a March 7 conference related to materials protected by the Classified Information Procedures Act (CIPA), according to federal court documents. The DOJ was asked to describe the “nature, scope, and volume” of the classified information at issue, along with any additional relevant details, after claiming it “may arise” and “be applicable in this case” in a Feb. 12 filing.

“CIPA”s fundamental purpose is to ‘harmonize a defendant’s right to obtain and present exculpatory material [at] trial and the government’s right to protect classified material in the national interest,'” the DOJ said, citing previous case law.

“The Supreme Court has acknowledged the importance of protecting the nation’s secrets from disclosure: ‘The Government has a compelling interest in protecting both the secrecy of information important to our national security and the appearance of confidentiality so essential to the effective operation of our foreign intelligence service,” the filing said.

Prosecutors noted how the government “produces discoverable information” to the defense in cases involving classified information. But the discovery of classified information must actually be helpful to the defense of the accused, according to the filing. Cannon ruled Friday that the DOJ made a “sufficient showing” that the information at issue was classified.

“The court finds that the United States properly invoked the provisions of CIPA and its classified information privilege as to the information referenced,” Cannon said. “The United States’ motion and all accompanying material are hereby sealed, and shall remain preserved in the custody of the Classified Information Security Officer, in accordance with established court security procedures, to be made available to the appellate court in the event of an appeal.”

Routh, 59, is scheduled to go before a jury in September after pleading not guilty to charges of attempting to assassinate a major presidential candidate, assaulting a federal officer and multiple firearm violations. He asked Cannon, a Trump appointee, last month if he could dump his public defenders and represent himself, to which she obliged — sparking fears that his trial will “become a circus,” according to federal prosecutors.

Routh tried to flex his legal muscles on July 23 in a pro se response to a DOJ motion filed weeks earlier, which asked Cannon to exclude “irrelevant and prejudicial evidence” that prosecutors expect to be filed by the defense and to admit certain trial evidence, including messages authored by Routh’s former employee Tina Cooper, who pleaded guilty in North Carolina for conspiring with Routh to help get his hands on weapons illegally.

The Justice Department torched Routh in its reply to his filing, saying he was “mistaken” on numerous things that he alleged in the response, including an “odd claim” that the government has not identified specific pieces of evidence at issue.

“As outlined below, to the best of our ability lacking a defense exhibit list, we have done so,” the DOJ said. “And our arguments are more persuasive in light of the defendant’s decision to represent himself. This court has a responsibility to ensure that trial does not become a circus, and that the jury is not burdened and distracted by plainly inadmissible evidence.”

In addition to trying to kill Trump, Routh is also accused of possessing a firearm while a convicted felon and for possessing a gun with an “obliterated serial number,” offenses punishable by up to 15 years and 5 years respectively upon conviction. The Department of Justice says that two people helped illegally obtain a weapon “on his behalf,” specifically the SKS rifle that he allegedly brought to Trump International Golf Club, according to prosecutors.

In his response to the DOJ’s motion, Routh rambled about the “new DOJ, Trump, Bondi” and how one can’t “besmirch the Presidents morals when he has none,” according to the filing. “The defendant respectfully moves this court to recognize that the prosecution is making every attempt in this motion to silence the defense in every fashion,” Routh alleged.

Prosecutors have said they expect the Florida man to present statements from self-published “books” and other writings of his, as well as hearsay statements.

“It is the defendant’s evidence that is most likely to upend this trial by injecting irrelevant and prejudicial facts unrelated to the actual charges,” the DOJ blasted in its reply.

“None of the substantive legal arguments raised … has merit,” prosecutors said.