I think BM already gets a big break: BM has the benefit that character evidence of the defendant is not admissible under the rules of evidence until the penalty phase of the trial so the jury really won't get to hear about the real BM until he's convicted. MOO
I agree with your thought in general, but I'd like to point out that Colorado Rule of Evidence 404 (a)(1) offers BM an opportunity to open the door by presenting evidence of his good character. This seem an act of desperation, but I have seen it work against considerable odds.
Here's the recently updated rule:
Colo. R. Evid. 404
As amended through Rule Change 2021(17), effective July 23, 2021
Rule 404 - Character Evidence; Other Crimes, Wrongs, or Acts
(a)
Character evidence generally. Evidence of a person's character or a trait of his character is not admissible for the purpose of proving that he acted in conformity therewith on a particular occasion, except:
(1)
Character of accused. In a criminal case, evidence of a pertinent trait of his character offered by an accused, or by the prosecution to rebut the same or if evidence of the alleged victim's character for aggressiveness or violence is offered by an accused and admitted under Rule 404(a)(2), evidence of the same trait of character of the accused offered by the prosecution;
(2)
Character of alleged victim. In a criminal case, evidence of a pertinent trait of character of the alleged victim of the crime offered by an accused, or by the prosecution to rebut the same, or evidence of a character trait of peacefulness of the alleged victim offered by the prosecution in a homicide case to rebut evidence that the alleged victim was the first aggressor;
(3)
Character of witness. Evidence of the character of a witness as provided in Rules 607, 608, and 13-90-101.
(b)
Other crimes, wrongs, or acts.
(1)
Prohibited Uses. Evidence of any other crime, wrong, or act is not admissible to prove a person's character in order to show that on a particular occasion the person acted in conformity with the character.
(2)
Permitted Uses. This evidence may, be admissible for another purposes,such as proving motive, opportunity, intent, preparation, plan, knowledge, identity, absence of mistake, or lack of accident,
(3)
Notice in a Criminal Case. In a criminal case, the prosecutor must:
(A) provide reasonable notice of any such evidence that the prosecutor intends to offer at trial, so that the defendant has a fair opportunity to meet it;
(B) articulate in the notice the permitted purpose for which the prosecutor intends to offer the evidence and the reasoning that supports the purpose; and
(C) do so in writing before trial - or in any form during trial if the court, for good cause, excuses lack of pretrial notice.
CRE 404
Source: (a) amended and adopted June 20, 2002, effective July 1, 2002; (a)(1), (a)(2), and (b) amended and effective September 27, 2007; amended and Adopted March 29, 2021, effective July 1, 2021.