As part of the Sixth Amendment right to confrontation, a defendant must be given great latitude to show any fact that would tend to establish ill feeling, bias, motive, or animus on the part of a witness testifying against him. Delaware v. Van Arsdall, 475 U.S. 673, 678-79, 106 S. Ct. 1431, 1434-35, 89 L. Ed. 2d 674 (1986); Davis v. Alaska, 415 U.S. 308, 316-17, 94 S. Ct. 1105, 1110-11, 39 L. Ed. 2d 347 (1974); Hurd v. State, 725 S.W.2d 249, 252 (Tex.Crim.App.1987); Pointer v. Texas, 380 U.S. 400, 403, 85 S. Ct. 1065, 1067-68, 13 L. Ed. 2d 923 (1965) (Fourteenth Amendment incorporates confrontation right). Our rules of criminal evidence expressly recognize the right to impeach a witness by proof of circumstances or statements showing bias or interest on the part of the witness. TEX. R. EVID. 613(b). Unlike an attack on a witness's character, which reflects on the witness's truth-telling tendencies generally, an attack concerning bias or interest relates only to the specific litigation or parties. Gonzales v. State, 929 S.W.2d 546, 549 (Tex.App.-Austin 1996, pet. ref'd). The impeaching party must attempt to show that the witness's attitude is such that he is likely to favor or disfavor a particular litigant's position for reasons unrelated to the merits of the suit. Id.;1 STEVEN GOODE, OLIN GUY WELLBORN III & M. MICHAEL SHARLOT, TEXAS PRACTICE: GUIDE TO THE TEXAS RULES OF EVIDENCE: CIVIL AND CRIMINAL 613.6 ( 2d ed. 1993 & Supp. 1999) (hereafter "Guide to Texas Evidence "). The rules of evidence grant a party greater latitude to prove a witness's bias than to prove a witness's untruthful character. Gonzales, 929 S.W.2d at 549. For the purpose of impeaching his credibility, a witness's character may be attacked by opinion or reputation evidence and by proof of certain criminal convictions. Id.; TEX. R. EVID. 608(a), 609. Other than conviction of a crime, a witness's character for truthfulness may not be impeached by proof of specific instances of conduct. Id. Rule 608(b) is very restrictive and allows for no exceptions. Ramirez v. State, 802 S.W.2d 674, 676 (Tex.Crim.App.1990). Rule 613, by contrast, places no limits on the sort of evidence that may be adduced to show a witness's bias or interest. Evidence of bias or interest covers a wide range, and the field of external circumstances from which probable bias or interest may be inferred is infinite. Jackson v. State, 482 S.W.2d 864, 868 (Tex.Crim.App.1972). The trial court has considerable discretion in determining how and when bias may be proved, and what collateral evidence is material for that purpose. Green v. State, 676 S.W.2d 359, 363 (Tex.Crim.App.1984). The defendant's right to confront witnesses does not prevent a trial court from imposing reasonable restrictions on cross-examination into the bias of a witness. Hurd, 725 S.W.2d at 252. The trial court may impose reasonable limits on cross-examination "based on concerns about, among other things, harassment, prejudice, confusion of the issues, the witness' safety, or interrogation that is repetitive, or only marginally relevant." Van Arsdall, 475 U.S. at 679, 106 S. Ct. at 1435; Miller v. State, 741 S.W.2d 382, 389 (Tex.Crim.App.1987).