The plaintiff-respondent-petitioner State of Wisconsin (State) seeks review of an unpublished decision of the court of appeals which *32reversed a judgment of conviction in the circuit court for Milwaukee County, the Honorable Charles B. Schudson presiding, after a jury found the defendant-appellant Henry F. McCall (McCall) guilty of second-degree reckless injury, contrary to Wis. Stat. § 940.23(2) (1991-92). The court of appeals concluded that McCall's constitutional right to confront his accusers1 was violated when the circuit court would not permit his counsel to cross-examine the victim regarding the dismissal of three charges2 pending against him prior to his testimony at McCall's trial. See State v. McCall, No. 94-1213-CR, unpublished op. at 2 (Wis. Ct. App. Mar. 28, 1995). The appellate court reversed the judgment of conviction and remanded for a new trial. Id.
The issue before the court on this review is whether the court of appeals erred as a matter of law when it failed to give deference to the circuit court's discretionary act of limiting the scope of cross-examination. We hold that the circuit court did not erroneously exercise its discretion or otherwise err when it concluded that defense inquiry on cross-examination regarding the three dismissed charges was not relevant, and therefore inadmissible. The circuit court found that any relevance of the proffered evidence was outweighed by other considerations, including the risk of unfair prejudice, a strong potential for confusing the *33issues, and a waste of valuable trial time. See Wis. Stat. § 904.03 (1993-94).3
HH
On February 22, 1992, Robert Wade (Wade) entered the apartment of his friend McCall, an individual from whom he had purchased cocaine in the past. Wade had been drinking and smoking cocaine in celebration of his birthday on that evening, prior to going up to McCall's residence. The facts regarding Wade's entry into the apartment and the ensuing scuffle between Wade and McCall are disputed. What is clear is that Wade's wife, Kathleen Wade, was in McCall's apartment when Wade arrived. Some form of altercation took place, and Wade was eventually shot in the shoulder by McCall. The bullet permanently lodged in Wade's spinal column, resulting in a quadriplegic condition which has confined him to a wheelchair. On the evening of the incident, he stated that he and McCall had been arguing, McCall had hit him on the head with the gun and shortly thereafter, shot him in the shoulder.
In June 1992, several months after the shooting occurred, Wade was interviewed by a police detective at his home. In recounting the events which had transpired in February, Wade stated to the officer that the only thing that he could remember that night was knocking on McCall's apartment door and later waking up in the hospital. At trial, Wade testified that after *34knocking upon McCall's door, McCall opened the door and let him in. McCall then closed and locked the door behind Wade. According to Wade's testimony, McCall then turned around with a gun in his hand and put it at Wade's shoulder. Wade's wife was hiding in the bathroom at the time and did not witness the shooting. Wade could not remember the gun discharging, but simply stated that the last thing he could remember was McCall pushing the gun into his shoulder. He then testified that he could not recall anything else that happened that evening until he awoke in the hospital and was being questioned by a police detective.
McCall's version of the events that evening were substantially dissimilar. McCall claimed that he shot Wade in self-defense, stating that after answering the knock on the door, and seeing that it was Wade, he attempted to shut the door, not intending to grant Wade entry into the apartment. Wade allegedly forced his way past the door and made threatening gestures directed at McCall. In response, McCall testified that he hit him on the head with the gun, so as to alleviate any further struggle. When Wade persisted, McCall shot him in the shoulder.
Wade represented the State's primary witness to refute McCall's self-defense theory. During cross-examination of Wade, McCall attempted to impeach the witness by inquiring into the nature of an alleged agreement between Wade and the prosecutor regarding the recently dismissed charges pending against him. Though Wade specifically denied that any agreement in fact existed, the State objected, and a hearing was conducted outside the presence of the jury.
The circuit court sustained the State's objection, denying the defense permission to proceed with this line of questioning during cross-examination. The cir*35cuit court judge articulated on the record the factors which he had considered in concluding that the proffered evidence was irrelevant and why its limited probative value was substantially outweighed by the danger of confusing the issues and wasting time on speculative and collateral matters. McCall was subsequently convicted of the lesser-included charge, second-degree reckless injury. Further facts will be noted as necessary in this opinion.
h*H
McCall argues that it was reversible error for the circuit court to prohibit defense counsel from cross-examining Wade regarding the dismissal of three charges which had been pending prior to the start of McCall's trial.4 The extent and scope of cross-examination allowed for impeachment purposes is a matter within the sound discretion of the circuit court. Rogers v. State, 93 Wis. 2d 682, 689, 287 N.W.2d 774 (1980); Chapin v. State, 78 Wis. 2d 346, 352, 254 N.W.2d 286 (1977). "The appellate court should reverse a trial court's determination to limit or prohibit a certain area of cross-examination offered to show bias only if the trial court's determination represents a prejudicial abuse of discretion." State v. Lindh, 161 Wis. 2d 324, 348-49, 468 N.W.2d 168 (1991) (citing State v. Whiting, 136 Wis. 2d 400, 422, 402 N.W.2d 723 (Ct. App. 1987)).5 *36No abuse of discretion will be found if a reasonable basis exists for the circuit court's determination. State v. Oberlander, 149 Wis. 2d 132, 140-41, 438 N.W.2d 580 (1989).
During cross-examination, the defendant sought to probe the circumstances surrounding the dismissal of charges which had been pending against Wade prior to trial. As the sole eyewitness for the prosecution, the accuracy and truthfulness of Wade's testimony were key elements in the State's case. The nature of the inquiry was clearly directed to effectuate an attack on the credibility of Wade as a witness, designed to reveal possible biases, prejudices, or ulterior motives that Wade may have possessed, as they directly related to his testimony against the defendant.6 The State, however, objected to this line of inquiry on relevancy *37grounds. See Wis. Stat. § 904.01 (1993-94).7 This court and the United States Supreme Court have recognized that a defendant's opportunity to explore the subjective motives for the witness's testimony is a necessary ingredient of a meaningful cross-examination.8
In Rogers, this court pronounced that "[t]he proper standard for the test of relevancy on cross-examination is not whether the answer sought will elucidate any of the main issues in the case but whether it will be useful to the trier of fact in appraising the credibility of the witness and evaluating the probative value of the direct testimony." Rogers, 93 Wis. 2d at 689 (citing McCormick, Evidence, § 30 (2d Ed. 1972)). Moreover, in Lindh, we highlighted the circumstances under which courts have properly excluded bias evidence:
Other courts have delineated some of the prejudice factors which may warrant the exclusion of bias evidence. One factor is whether the evidence would divert the trial to an extraneous issue. Hossman v. State, 467 N.E.2d 416, 418 (Ind. 1984). A court can and should exclude bias evidence which has little *38bearing on the witness's credibility, but which would impugn the witness's character because such evidence "opens the door to improper considerations and lends to the confusion of the jury by placing undue emphasis on collateral matters." People v. Cole, 654 P.2d 830, 833 (Colo. 1982). If the bias evidence, taken as a whole, might have directed the jury's attention away from the case under consideration, it may be prejudicial. Id. at 834.
The trial court may exclude bias evidence if the very slight probative value of the evidence on the issue of bias fails to overcome its strong likelihood of confusing the issues and undue delay. United States v. Jarabek, 726 F.2d 889, 902 (1st Cir. 1984). The appellate court should not find the trial court abused its discretion when the relevance of the proffered bias evidence was unclear and the risk of prejudice was real. United States v. Sellers, 658 F.2d 230, 232 (4th Cir. 1981). The trial court may prohibit cross-examination in a certain area where to permit it would open up extraneous matters, for the trial court " 'has responsibility for seeing that the sideshow does not take over the circus.'" United States v. Brown, 547 F.2d 438, 446 (8th Cir. 1977).
Lindh, 161 Wis. 2d at 363.9
Before deciding whether to grant McCall's request to explore what he perceived to be a "working relationship" between Wade and the prosecutor regarding trial testimony and the dismissal of pending charges, the *39circuit court gave heed to the extensive arguments of counsel in a hearing conducted outside the jury's presence. After balancing the relevancy of the proffered evidence against the danger of unfair prejudice and confusion of the issues, see Wis. Stat. § 904.03 (1993-94), the circuit court demonstrated a logical reasoning process in sustaining the State's objection to continued inquiry into this line of questioning. The circuit court reasoned that the dismissal of the three charges did not notably affect Wade's testimony at trial, stating:
When we compare the statement given to the police and the statement given in court, that's simply not so. It is a very small difference that would be typical. A difference between a summary of the victim's statement immediately after an event given to police and testimony in court.
Next, the difference that does exist relates to whether the victim remembers nothing at all or remembers something being put to his shoulder. Well, that is a difference on something that as I understand it is not in dispute.
From what I understand the defense theory is here, there is not a denial that there was a gun, there's not a denial that there was a gunshot, there's not a denial that the defendant was the shooter. So in this very small area of difference, we are not entering any area of dispute whatsoever.
Another way I suppose to phrase that is that if in fact the witness had suddenly decided to remember things that he didn't really remember, he certainly would be remembering much more than he says he remembers today.
With all that in mind, I do not see any proper basis on which the Court should allow there to be questioning on what would prove to be a wholly distracting and speculative area.
*40The lack of any demonstrable impact of the dismissal of charges on Wade's testimony was but one of the various factors considered by the circuit court in exercising its discretion to limit the scope of cross-examination. Compare State v. Nerison, 136 Wis. 2d 37, 46, 401 N.W.2d 1 (1987) (discussing the need for full disclosure of terms of agreements struck with witnesses in order to preserve defendant's right to fair trial).
In reaching its decision, the court contemplated the prosecutor's benign grounds for dismissing the pending charges against Wade, namely, his permanently paralyzed state which would make incarceration difficult and would effectively prevent Wade from committing assaultive crimes or stealing cars in the future. The prosecutor further indicated that Wade's involvement in vocational rehabilitation, drug and alcohol therapy, as well as physical therapy, did not warrant his placement on probation, as to do so would simply be a waste of time and resources.
Though given the opportunity to discredit these pronouncements, McCall was unable to offer any proof to substantiate his claim of a clandestine agreement between Wade and the prosecutor. The record in this case bolsters the conclusion that the minimal variance in Wade's trial testimony would not support a reasonable inference that Wade was cooperating in accord with the terms of a prosecutorial deal, or perhaps, even, that he believed he may have been doing so. Thus, we find that a defense inquiry based upon this purely speculative theory is too far afield of any rational relationship to the truthful character of the witness or his testimony to consider it a prejudicial exercise of discretion to exclude the proffered testimony.
*41Moreover, the record is replete with evidence offered by McCall to afford the jury a basis to infer that Wade's credibility was such that he would be less likely than the average trustworthy citizen to be truthful in his testimony. Defense counsel was able to solicit the following information regarding Wade's character for truthfulness during cross-examination: Wade had ten prior criminal convictions; he had been in prison and had problems with alcohol; Wade had bought cocaine from McCall on more than one occasion; he had been drinking all day and had smoked cocaine prior to the shooting; Wade was attending drug and alcohol counseling at the time of trial; he had a bad temper but claimed to have learned how to control it over the years; and finally, Wade could not recall giving a statement to police on June 15, even though this was only a month before trial and he had in fact given such a statement.
The introduction of this evidence to the jury regarding the truthful character of the State's key witness was reiterated again during closing arguments. The jury's conviction on the lesser-included offense of second-degree reckless injury would seem to support the State's contention that the evidence admitted was in fact utilized to discredit the testimony offered by Wade, as the jury was not able to conclude beyond a reasonable doubt that McCall had acted with utter disregard for human life, an element required for conviction of the charge of first-degree reckless injury. See Wis. Stat. § 940.23(1) (1993-94). Brief for Petitioner at 30.
Although a defendant is entitled to significant latitude regarding the extent and scope of an inquiry to explicate the witness's bias, it is the duty of the circuit *42court to curtail any undue prejudice by limiting cross-examination, including the exclusion of bias evidence which would divert the trial to extraneous matters or confuse the jury by placing undue emphasis on collateral issues. The circuit court did not erroneously exercise its discretion when it concluded that further inquiry into the existence of an alleged, though unproven agreement, would be wholly distracting and speculative. The bias evidence which McCall wished to introduce would have unnecessarily directed the jury's attention away from the case under consideration, and would have been unduly prejudicial.
After considering the appropriate law and relevant facts, the circuit court exercised its discretionary authority to limit cross-examination, concluding that any relevance of the proffered evidence was outweighed by these statutory considerations. See Wis. Stat. § 904.03 (1993-94). We therefore find that the court of appeals erred as a matter of law when it substituted its discretion for that of the circuit court.
III
We now turn to the court of appeals conclusion, involving an issue raised sua sponte, that because the circuit court refused to permit cross-examination involving the dismissed charges, McCall was imper-missibly denied his right to confront witnesses against him under the Sixth Amendment to the United States Constitution.10 McCall, No. 94-1213-CR, unpublished *43op. at 4. Due to the fact that the testimony which McCall sought to elicit was not relevant, by definition, we find that McCall's confrontation right under the Sixth Amendment was not violated.
This court and the United States Supreme Court have recognized that a defendant's right to confront the witnesses against him is central to the truthfinding function of the criminal trial. Maryland v. Craig, 497 U.S. 836, 845-47 (1990); Ohio v. Roberts, 448 U.S. 56, 64 (1980); Mattox v. United States, 156 U.S. 237, 242-43 (1895); Rogers, 93 Wis. 2d at 692-93. In Davis v. Alaska, 415 U.S. 308 (1974), the United States Supreme Court declared that "[t]he main and essential purpose of confrontation is to secure for the opponent the opportunity of cross-examination." Id. at 315-16 (quoting 5 J. Wigmore, Evidence, § 1395, p. 123 (3d. ed. 1940)). The right of cross-examination is more than a desirable rule of trial procedure. It is, indeed, "an essential and fundamental requirement for the kind of fair trial which is this country's constitutional goal." Pointer v. Texas, 380 U.S. 400, 405 (1965).
However, the right to confront and to cross-examine is not absolute and may, in appropriate cases, bow to accommodate other legitimate interests in the criminal trial process. Chambers v. Mississippi, 410 U.S. 284, 295 (1973). As acknowledged in the case of Delaware v. Van Arsdall, 475 U.S. 673 (1985):
It does not follow, of course, that the Confrontation Clause of the Sixth Amendment prevents a trial *44judge from imposing any limits on defense counsel's inquiry into the potential bias of a prosecution witness. On the contrary, trial judges retain wide latitude insofar as the Confrontation Clause is concerned to impose reasonable limits on such 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. And as we observed earlier this Term, "the Confrontation Clause guarantees an opportunity for effective cross-examination, not cross-examination that is effective in whatever way, and to whatever extent, the defense might wish." Delaware v. Fensterer, 474 U.S. 15, 20 (1985) (per curiam) (emphasis in original).
Id. at 679. This court has similarly stated that while the right to confront one's accusers is protected by the constitution, this right is not violated when the court precludes a defendant from presenting evidence which is irrelevant or immaterial. Rogers, 93 Wis. 2d at 692-93.11
As indicated earlier, we find that the circuit court properly exercised its discretionary authority to limit the scope of cross-examination, foreclosing the defense from presenting speculative and irrelevant evidence designed to confuse the issues in the instant case, and interject undue prejudice into the jury's decision making process. We conclude that the circuit court did not err in its ruling, and thus, there was no constitutional *45violation in precluding McCall from introducing such evidence.
By the Court. — The decision of the court of appeals is reversed.
The confrontation clause issue was raised sua sponte by the appellate court. It was not the basis for the defendant's response to the State's objection at trial, nor was it argued in his appellate brief.
The charges included battery, resisting an officer, and operating a motor vehicle without owner's consent.
Section 904.03 provides as follows:
Although relevant, evidence may be excluded if its probative value is substantially outweighed by the danger of unfair prejudice, confusion of the issues, or misleading the jury, or by considerations of undue delay, waste of time, or needless presentation of cumulative evidence.
Although McCall did not file a brief in the supreme court, this argument was presented in his brief to the court of appeals and is relevant to our review today.
Moreover, in Hartung v. Hartung, 102 Wis. 2d 58, 66, 306 N.W.2d 16 (1981), this court stated:
A discretionary determination, to be sustained, must demonstrably be made and based upon the facts appearing in the record and in *36reliance on the appropriate and applicable law. Additionally, and most importantly, a discretionary determination must be the product of a rational mental process by which the facts of record and law relied upon are stated and are considered together for the purpose of achieving a reasoned and reasonable determination. It is recognized that a trial court in an exercise of its discretion may reasonably reach a conclusion which another judge or another court may not reach, but it must be a decision which a reasonable judge or court could arrive at by the consideration of the relevant law, the facts, and a process of logical reasoning.
The change in testimony which McCall suggests is critical to the inference that some form of "dismissal for false testimony" agreement was in place involved Wade's contention for the first time at trial that the last thing he remembered was the defendant putting what appeared to be a gun to his shoulder. As recognized by the circuit court, the significance placed upon this minimal discrepancy by McCall is misplaced. At trial, McCall admitted that he was the one who had shot Wade in the upper chest, arguing that the shooting was in self-defense. Therefore, there was. no dispute as to who shot Wade, or how he was shot.
*37Further inquiry into this area would have proven both unnecessarily cumulative and a waste of trial time.
Section 904.01 provides as follows:
'Relevant evidence' means evidence having any tendency to make the existence of any fact that is of consequence to the determination of the action more probable or less probable than it would be without the evidence.
State v. Lenarchick, 74 Wis. 2d 425, 448, 247 N.W.2d 80 (1976). In Davis v. Alaska, 415 U.S. 308 (1974), the United States Supreme Court suggested that rather than accepting the witness's denial concerning bias, cross-examination should be permitted "to expose to the jury the facts from which jurors, as the sole triers of fact and credibility, could appropriately draw inferences relating to the reliability of the witness." Id. at 318.
See also Delaware v. Van Arsdall, 475 U.S. 673, 679 (1986) (holding that bias evidence which is only marginally relevant or which may confuse the issues is excludable); State v. Williamson, 84 Wis. 2d 370, 384-85, 267 N.W.2d 337 (1978) (stating that evidence which is relevant to provide bias "must also satisfy sec. 904.03, Stats., requiring the trial court to weigh the probative effect of the evidence against its prejudicial effect").
The sixth amendment to the Constitution provides in part: "In all criminal prosecutions, the accused shall enjoy the right ... to be confronted with the witnesses against him; to have compulsory process for obtaining witnesses in his favor ...." The Wisconsin Constitution, art. I, § 7 provides as follows:
*43"In all criminal prosecutions the accused shall enjoy the right ... to meet the witnesses face to face; to have compulsory process to compel the attendance of witnesses in his behalf...."
See also Chapin v. State, 78 Wis. 2d 346, 353, 254 N.W.2d 286 (1977); State v. Becker, 51 Wis. 2d 659, 666-67, 188 N.W.2d 449 (1971); Milenkovic v. State, 86 Wis. 2d 272, 286, 272 N.W.2d 320 (Ct. App. 1978).