Although Colorado’s second-highest court has issued multiple decisions in recent months upholding a revised definition of “reasonable doubt” from three years ago, an appellate judge became the first on Thursday to argue that a key phrase violates defendants’ constitutional right to due process.

Judge Michael H. Berger warned that, in his view, it is problematic to instruct jurors they must acquit when there is “a real possibility the defendant is not guilty.” Among other things, he worried that the phrasing appeared to assume the defendant’s guilt.

“It suggests that the defendant is guilty unless there is a real possibility that he is not guilty. However, a defendant has no obligation to prove that he is not guilty or even that there is a real possibility that he is not guilty,” Berger wrote.

Before 2023, Colorado’s template jury instructions for criminal cases contained a longstanding explanation of reasonable doubt: A doubt based upon reason and common sense, which was not vague or speculative, that would “cause reasonable people to hesitate to act in matters of importance to themselves.”

Then, in January 2023, the judicial branch announced a small group of judges had voted to change the language of the model instruction. The revision advised jurors to vote to convict if they were “firmly convinced of the defendant’s guilt.”

“But if you think there is a real possibility that the defendant is not guilty,” the instruction continued, “then the prosecution has failed to prove the crime charged beyond a reasonable doubt.”

The 2023 update resembled the reasonable doubt instruction used in Colorado’s federal trial courts, and the language was endorsed by U.S. Supreme Court Justice Ruth Bader Ginsburg in 1994 as a “clear, straightforward, and accurate” definition of reasonable doubt for jurors.

Nonetheless, defense attorneys were concerned the change lessened the prosecution’s burden to prove a defendant guilty. Earlier this year, the state’s Court of Appeals issued a pair of precedent-setting decisions upholding the new wording as constitutional. Multiple other opinions have since followed suit.

In the current case, a Broomfield jury found Ever Ulises Berumen guilty on three counts of sexual exploitation of a child and one count of invasion of privacy. He challenged the use of the 2023 reasonable doubt instruction, but a three-judge appellate panel maintained there was no problem.

The Dec. 11 majority opinion acknowledged that some courts elsewhere in the country have disapproved of the “firmly convinced” language, but only because it tracked too closely with the lower standard of “clear and convincing evidence.”

Colorado’s revised instruction “makes the distinction between the two standards clear,” wrote Judge Craig R. Welling for himself and Judge Grant T. Sullivan — both of whom participated in the earlier precedent-setting decisions upholding the new definition.

Berger, a retired judge who sat on the panel assigned by the chief justice, did not believe the new language provided a constitutionally sound definition of reasonable doubt, given the instruction to acquit if there is a “real possibility that the defendant is not guilty.”

“Juries may acquit on many permissible bases,” he wrote, “including that (1) there is no evidence of guilt; (2) while there is some evidence of guilt, the prosecution has not presented proof establishing guilt beyond a reasonable doubt; or (3) the prosecution has not disproved beyond a reasonable doubt any affirmative defense” like self-defense.

He elaborated that juries may find a defendant guilty of the charged offense but ultimately acquit because the prosecution has not proven everything it must prove. With Berumen’s case, Berger thought jurors potentially convicted him because they saw no “real possibility” he did not commit sex acts with the victim — even though the disputed issue was whether he knew the victim was under 18.

It is “unwise to continue to use a model instruction that is reasonably susceptible of that meaning,” Berger concluded.

The Colorado Supreme Court announced in September that it would review the constitutionality of the revised definition in another case.

The case is People v. Berumen.