OPINION
Defendant appeals his convictions for aggravated assault with a deadly weapon with a firearm enhancement and two counts of aggravated battery with a firearm enhancement. He contends the trial court erred in excluding testimony concerning one victim’s predilection for violence and in refusing to give certain jury instructions. We reverse on the first issue and therefore need not address the second.
FACTS
Defendant raised the issues of self-defense and defense of others. His version of the pertinent facts, most of which were contradicted by other witnesses, is as follows. Defendant, his father, and a friend named Edwin Vigil were walking on a sidewalk. One of the victims, named Sam Romero, drove by and pulled up next to the sidewalk. A verbal argument ensued, which ended when Romero jumped the curb with his car and attempted to run over defendant’s father. After buying a six-pack of beer and consuming it with the other two men, defendant decided to go talk to Romero to determine what caused the earlier altercation. Defendant and Vigil walked to Romero’s home and entered. Vigil, who was also Romero’s neighbor, went into the kitchen and greeted Romero. Romero and Vigil then came out of the kitchen and Romero saw defendant, whereupon he turned around and re-entered the kitchen. Vigil and defendant followed. As they entered the kitchen, Romero grabbed a steak knife and took several steps toward Vigil. Defendant pulled out a gun and told Romero to drop the knife. Instead, Romero took another step toward Vigil with knife in hand. Defendant then shot Romero, shot a man who had been sitting in a chair near defendant but had jumped up at the first shot, and shot at another man who also jumped. Defendant and Vigil then hurriedly exited the house.
At trial, defendant attempted to testify about Romero’s reputation in the community for violence. He testified on direct examination that he knew Romero for maybe three years. The state objected, arguing in essence that defendant could not himself testify about Romero’s reputation, but had to bring in another witness to do so. Defense counsel responded by contending that defendant’s knowledge of Romero’s violent character explained why defendant had reacted with such force to Romero’s actions in the house. Counsel argued that defendant had heard that Romero would threaten to shoot young men who were dating his daughters, and had bragged about wearing a chain of people’s ears around his neck when he was in Vietnam. The court ruled that the evidence was hearsay and refused to allow the questioning. Defendant then made an offer of proof in which he testified that Romero's reputation in the community for violence was “bad.” The basis for defendant’s view of Romero’s reputation was his knowledge of Romero’s alleged actions in Vietnam, cutting off people’s ears and wearing them around his neck, and his alleged statements that he “had a bullet” for anybody involved in disputes about his daughters. Following the offer of proof the trial court reiterated its ruling.
DISCUSSION
Defendant’s proffered testimony consisted of two types of testimony, general testimony about Romero’s reputation for violence, and evidence of specific instances of conduct that gave rise to the asserted reputation. See SCRA 1986, 11-405(A) (reputation evidence) and (B) (specific conduct). We must decide whether the trial court abused its discretion in excluding this evidence. See State v. Ewing, 97 N.M. 235, 638 P.2d 1080 (1982) (admission of character testimony is a matter within the sound discretion of the trial court). Under the circumstances of this case, we hold that the reputation evidence and the Vietnam conduct evidence was of such importance to defendant’s defense that the exclusion was an abuse of discretion. See State v. Dun *796 can, 111 N.M. 354, 805 P.2d 621 (1991) (evidence of coercer’s character was so important to defendant’s duress defense that it was an abuse of discretion to exclude it). We need not address the testimony concerning Romero’s alleged threats against his daughters’ boyfriends, although we are inclined to agree with the state that this testimony was vague and not as probative of character as actual actions, and the exclusion of the testimony therefore was not an abuse of discretion.
In self-defense or defense-of-others cases, evidence of the victim’s character may be admissible to show either defendant’s reasonable fear and response under the circumstances, or that the victim was the aggressor. Cf State v. Montoya, 95 N.M. 433, 622 P.2d 1053 (Ct.App.1981). The victim’s reputation for violence and any prior violent acts committed by the victim are relevant to both issues. State v. Melendez, 97 N.M. 740, 643 P.2d 609 (Ct.App.1981), rev’d on other grounds, 97 N.M. 738, 643 P.2d 607 (1982) (tendered evidence of victim’s reputation for violence was relevant to defendant’s claims that occupants of a car were aggressors and that he had reasonable apprehensions for his life and safety). Contrary to the trial court’s ruling, the hearsay rule is no bar to the introduction of such testimony, at least where, as here, the testimony is offered not for the truth of the matter asserted, but to show defendant’s state of mind. See SCRA 1986, 11-801(C); see also 2 J. Weinstein & M. Berger, Weinstein’s Evidence § 405[2] (1990) (reputation evidence is admissible despite the hearsay rule).
On appeal, the state has not attempted to defend the trial court’s use of the hearsay rule to exclude the evidence. Instead, the state argues that the court had discretion to exclude the evidence and the court’s decision should be upheld under the “right for any reason” doctrine. See State v. Beachum, 83 N.M. 526, 494 P.2d 188 (Ct.App.1972) (trial court’s decision will be affirmed if it is right for any reason, even if court offers erroneous rationale for its ruling). We are not convinced this is an appropriate situation in which to apply the doctrine. It is one thing to hold that, although the trial court’s rationale was wrong, another reason justifies the court’s decision. It is entirely another matter to hold that if the court had not been led astray, and had known it had discretion to admit or exclude the evidence under a different rule of evidence, it definitely would have exercised that discretion to exclude rather than admit the evidence. To affirm the trial court, we would have to predict that even if the court had realized the evidence was admissible, the court would have excluded it anyway in the exercise of its discretion. This would be a difficult task. Cf State v. Duncan (abuse of discretion analysis is unnecessary where trial court did not exclude evidence using the balancing test of Rule 403, but instead excluded evidence under Rule 404); State v. Ferguson, 111 N.M. 191, 803 P.2d 676 (Ct.App.1990) (discussing the necessity for trial courts to spell out the reasons for exercising their discretion, so the appellate court can determine whether the exercise of discretion had an erroneous legal basis). Neither party briefed this issue and we need not address it further.
Romero’s purported reputation for violence and his alleged gruesome behavior in Vietnam were obviously important factors in explaining why defendant reacted so strongly during the incident. If the jury had believed defendant’s description of Romero’s personality and had believed that defendant really did think Romero had cut off people’s ears' in Vietnam, it would have gone a long way toward explaining why defendant thought it was necessary to take a gun with him to Romero’s house and to use it during the incident. Without such testimony, all the jury knew was there had been an incident earlier that day, during which no physical contact had occurred, and defendant consequently felt he needed to be armed before talking with Romero. This information, standing alone, was a much less convincing explanation of *797defendant’s actions than it would have been had the jury also known that defendant thought of Romero as a violent individual who would not hesitate to use the knife he held as he approached Vigil. By excluding this evidencé, therefore, the trial court prevented defendant from developing a major part of his defense. This deprivation was an abuse of discretion. Cf State v. Duncan (where evidence is of great importance to a defense, exclusion of that evidence would be an abuse of discretion).
The state raises several arguments in support of its position that exclusion of the evidence was not an abuse of discretion. First, the state argues the evidence was cumulative. Defendant presented evidence concerning the prior incident in which Romero allegedly drove his car over the curb toward defendant, Vigil, and defendant’s father. There was also testimony, corroborated by Vigil, that Romero was approaching Vigil with a knife when defendant shot Romero. According to the state, this evidence was sufficient to explain why defendant thought it necessary to arm himself before talking to Romero and to use the weapon during the confrontation at the house. As we have discussed above, however, this information does not have the same convincing impact without the background knowledge concerning defendant’s view of Romero’s reputation and his knowledge of Romero’s past conduct. In addition, Romero denied that he had jumped the curb with his car and testified instead that defendant and his father kicked the car and were the aggressors in that incident. He also contradicted defendant’s and Vigil’s testimony concerning the shooting, claiming that he did not pick up a knife and did not approach Vigil. Other witnesses of the shooting corroborated Romero’s account. Since there was radically conflicting evidence about the incidents, defendant’s testimony about Romero’s reputation and past conduct was necessary to help the jury resolve the conflicts and decide who the aggressor was. Cf. State v. Brenner, 53 Wash.App. 367, 768 P.2d 509 (1989) (where witness’s own testimony established his aggressiveness, exclusion of evidence concerning witness’s past aggressive acts was not an abuse of discretion, because defendant was not denied his right to argue his theory of the case).
The state also argues that there was no evidence that defendant knew of Romero’s reputation or his past specific conduct at the time of the shootings. Where character evidence such as this is offered to establish a defendant’s reasonable apprehension of danger, the defendant must show he knew of the reputation or conduct at the time of the incident. State v. Ewing. During the offer of proof made through defendant’s own testimony, he never specifically stated that he knew of Romero’s reputation or the Vietnam conduct on the day of the shooting. However, defense counsel had earlier explained to the trial court, in summary form, what defendant’s testimony would be if he were allowed to testify. Counsel stated that defendant had heard Romero threaten to shoot young men who were dating his daughters and had heard Romero was bragging about carrying people’s ears around his neck in Vietnam, and that defendant had these remarks in mind during the incident. This was in effect an offer of proof through counsel that sufficiently apprised the trial court that the time period in question, regarding the issue of defendant’s knowledge, was the time of the incident. Cf SCRA 1986, 11-103(A)(2) (substance of excluded evidence must be made known to judge by offer or be apparent from context in which questions were asked).
The state maintains there was no abuse of discretion because the alleged conduct in Vietnam occurred long before the shooting. See State v. Ewing (no abuse of discretion in exclusion of thirty-two and thirty-three-year-old convictions, even if defendant had shown he knew about the convictions). We point out, first of all, that this argument has no applicability to the pure reputation testimony proffered by de*798fendant, to the effect that Romero’s reputation in the community for violence was bad. In addition, under the circumstances of this case, we do not agree with the state’s argument regarding the Vietnam conduct testimony. If the evidence of this conduct had been offered to prove Romero was the aggressor, the state's argument would have greater force. Actions taken during a war, fifteen or twenty years ago, might not shed much light on the actor’s propensities for violence today. The evidence in this case, however, was offered to show why defendant had such great apprehension for Vigil’s safety and his own safety. The idea that a person would cut ears from bodies and wear them around his neck has such an impact that it is unlikely the fact it occurred some time ago would diminish its effect on one’s state of mind. This specific conduct was not an ordinary criminal conviction, but was a remarkable indicator of defendant’s view of Romero’s propensity for violence. The focus is not on whether Romero actually committed the act, but on whether defendant believed- he did. Offered to prove Romero was the aggressor, the evidence of fifteen- to twenty-year-old conduct was not too reliable. Offered to prove defendant's belief regarding Romero’s willingness to use a knife on Vigil, however, the passage of time since the alleged conduct did not have much effect on the reliability of the evidence.
The state argues the prejudicial effect of this evidence outweighs its probative value, and exclusion was therefore proper. See SCRA 1986 11-403. Again, we point out that this argument does not appear to apply to the pure reputation testimony. The statement that Romero’s reputation for violence is “bad” has little prejudicial effect. In addition, because the issue regarding the conduct in Vietnam is not whether the conduct occurred, but the effect of the information on defendant, this case is unusual. Testimony that Romero cut off people’s ears is quite prejudicial, but the very gruesomeness of the information establishes the great impact it could have had on defendant’s state of mind during the shooting incident. Therefore, the probative value of the testimony is high. To exclude evidence because of its prejudicial effect, that effect must substantially outweigh its probative value. Rule 11-403. We do not believe exclusion was warranted on this basis. Cf. State v. Hogervorst, 90 N.M. 580, 566 P.2d 828 (Ct.App.1977) (fact that competent evidence prejudices a party is not grounds for exclusion; question is whether probative value is substantially outweighed by prejudicial effect).
CONCLUSION
Therefore, we believe that the reputation evidence and the Vietnam conduct evidence was of such importance to defendant’s defense that the exclusion of such evidence was an abuse of discretion. We also disagree with the dissent that the district judge did not exercise his discretion in ruling on the evidentiary question. The judge ruled on the objection, heard the offer of proof, and then reiterated his ruling that the reputation evidence should not be admitted. We see no point in remanding to allow the judge to rule upon an issue that has already been ruled upon. Based on the foregoing, we reverse the trial court and remand for a new trial.
IT IS SO ORDERED.
ALARID, C.J., concurs.
BIVINS, J., concurs in part, dissents in part and files an opinion.