[¶ 1] Lee Thurlow appeals from the judgment entered in the Superior Court (Cumberland County, Crowley, J.) following a jury trial in which he was found guilty of unlawful sexual contact pursuant to 17-A M.R.S.A. § 255(1)(A) (Supp.1997), assault pursuant to 17-A M.R.S.A. § 207 (1983 & Supp.1997), and attempted gross sexual assault pursuant to 17-A M.R.S.A. § 253(1)(A) (Supp.1997). Thurlow contends, inter alia, that the trial court erred in excluding testimony concerning the victim’s prior threats to falsify allegations of rape against him.1 We agree and vacate the judgment.
[¶ 2] Lee Thurlow’s convictions arise from an alleged incident between Thurlow and his former girlMend. Thurlow allegedly arrived at the victim’s home, entered, and forcibly attempted to have sex with her. The testimony revealed that, about thirteen months prior to this incident, the victim’s relationship with Thurlow ended when she became aware that Thurlow was having sexual relations with another woman. The victim became aware of Thurlow’s indiscretion while the two were staying at the apartment of Thurlow’s Mends, Larry Shumway and Susan McAleer. On the night that Thurlow and the victim ended their relationship, Thurlow contends that the victim, angered by Thurlow’s infidelity, told McAleer that, “he [Thurlow]. just fucked me and left. I should call the police on him. That’s rape.”
[¶ 3] During direct examination, the victim denied having made this statement. Thur-low was not permitted to present impeachment testimony from McAleer concerning this conversation. Thurlow made two arguments in support of the admissibility of McA-leer’s testimony concerning the victim’s statements: (i) they are prior inconsistent statements admissible for the purpose of im*520peaching her testimony; and (ii) they are excited utterances pursuant to M.R. Evid. 803(2). The court rejected both arguments and furthermore determined that, pursuant to M.R. Evid. 403, the probative value of McAleer’s testimony was outweighed by its potential adverse impact on the jury and therefore should be excluded. After a jury verdict of conviction, Thurlow filed a motion for a new trial based on the exclusion of the testimony concerning the victim’s threat to fabricate a rape charge against him. The motion was denied and this appeal followed.
I.
[¶ 4] The court correctly concluded that the victim’s statements were not excited utterances. The court erred, however, in concluding that the victim’s alleged out-of-court statements to McAleer did not constitute prior inconsistent statements. A prior inconsistent statement is a statement “offered not for the truth of the matter asserted but to demonstrate that the witness has in the past told a different story and therefore his [or her] trial testimony may not be reli-able_” State v. Marr, 551 A.2d 456, 458 (Me.1988). We have enunciated “two preconditions to the admission of an out-of-court statement under the prior inconsistent statement rule: the out-of-court statement must truly be inconsistent with the witness’s trial testimony ... and the impeachment must be on a matter that is ‘relevant’ as opposed to ‘collateral.’”' Id. (quotations and citations omitted).
[¶ 5] At trial, the victim denied that she had, about 13 months prior to the present incident, threatened to falsify a rape charge against Thurlow in the presence of McAleer. Thurlow subsequently sought to introduce testimony by McAleer that the victim did make this statement to McAleer. Such testimony would have described an out-of-court statement by the victim that directly contradicted her trial testimony. The court therefore erred in not finding an inconsistency.
II.
[¶ 6] The trial court also erred in excluding McAleer’s testimony on the basis of M.R. Evid. 403. Pursuant to M.R. Evid. 403, the trial court may exclude evidence “if its probative value is substantially' outweighed by the danger of unfair prejudice, confusion of the issues, or misleading the jury....” We review evidentiary rulings for clear error or abuse of discretion and accord “wide discretion” to the trial court’s evaluation of the potential for unfair prejudice. State v. Cloutier, 1997 ME 96, ¶5, 695 A.2d 550, 552; State v. Shuman, 622 A.2d 716, 718 (Me.1993). We have held, however, that when evidence is proffered by a criminal defendant and the State contends that the evidence is inadmissible, “the defendant’s right to confront and cross-examine the witnesses against him significantly circumscribes the court’s discretion to exclude the evidence.”2 State v. Graves, 638 A.2d 734, 737 (Me.1994)
[¶ 7] “[T]he exposure of a witness’ motivation in testifying is a proper and important function of the constitutionally protected right of cross-examination.” Davis v. Alaska, 415 U.S. 308, 316-17, 94 S.Ct. 1105, 39 L.Ed.2d 347 (1974). The right to introduce evidence to expose motive assumes particular importance when the criminal defendant faces damaging testimonial evidence from a witness who might be motivated by “malice, vindictiveness, intolerance, prejudice, or jealousy.” Davis, 415 U.S. at 317 n. 4, 94 S.Ct. 1105 (quoting Greene v. McElroy, 360 U.S. 474, 496, 79 S.Ct. 1400, 3 L.Ed.2d 1377 (1959)). Thurlow theorizes that if the victim was capable of threatening to falsify a rape charge against him then she is capable of falsifying the present charges against him; he claims that she is motivated in the present instance by the same malice, vindictiveness, and jealousy that led her to contemplate a false rape charge in the past.
[¶8] This case is functionally indistinguishable from Graves. In Graves, the trial court excluded evidence demonstrating possible bias of a witness against the defendant who was accused of raping her. Graves, 638 *521A.2d at 737. This witness had sold t-shirts prior to trial depicting the accused with his hands and penis in handcuffs and which stated “Ain’t gettin off ... this time ... they finally got ‘the big one’.” Id. at 736 n. 2. The trial court reasoned that the prejudicial value of this evidence outweighed its probative value in light of the other evidence produced demonstrating the witnesses dislike for the defendant. Id. at 737. We disagreed, noting that the sale of t-shirts by the witness demonstrated a distinct level of bias against the defendant and could not be characterized as cumulative bias evidence. Id. The excluded testimony of McAleer, like that excluded in Graves, was not merely cumulative evidence of the victim’s dislike for Thurlow; the excluded evidence demonstrated a distinct manifestation of vindictiveness toward Thur-low—a willingness to seriously contemplate a false retaliatory charge of rape.
[¶9] The testimony of McAleer is “the proper subject for jury consideration.” Graves, 638 A.2d at 739. The victim was the State’s principal witness against Thurlow, and thus “evidence tending to impeach her credibility ha[s] greatly enhanced probative value.” State v. Whitman, 429 A.2d 203, 205 (Me.1981). The adverse impact that this evidence may have on the jury cannot outweigh the probative value in these circumstances. See State v. Forbes, 445 A.2d 8, 12 (Me.1982) (“[adverse impact] means more than simply damage to the opponent’s cause ... [it is] an undue tendency to move the tribunal to decide on an improper basis, commonly, though not always, an emotional one”) (citations omitted). The trial court exceeded the bounds of its discretion in excluding the testimony concerning the victim’s threat to fabricate a rape charge against Thurlow. Because we cannot say beyond a reasonable doubt that the exclusion of this evidence did not affect the verdict, the error is not harmless and we vacate the judgment on this ground. See State v. Anaya, 438 A.2d 892, 894 (Me.1981).
The entry is:
Judgment vacated. Remanded for further proceedings consistent with the opinion herein.
. Thurlow also claims that the verdict was unlawfully tainted by a juror’s extra-judicial questioning of him concerning his decision not to testify. Because we vacate the judgment on the ground that the trial court improperly excluded Thurlow’s proffered evidence regarding the victim’s motive we need not reach the issue of the improper contact during trial between a juror and Thurlow. See Your Home, Inc. v. City of Portland, 432 A.2d 1250, 1256-57 (Me.1981) (”[W]e avoid expressing opinions on constitutional law whenever a nonconstitutional resolution of the issues renders a constitutional ruling unnecessary.”).
. This right of confrontation is secured by the United States and Maine constitutions. U.S. Const, amend. VI; Me. Const, art I, § 6.