James Schultz appeals from a judgment of conviction of first-degree murder and from *372an order denying his post-conviction motions. The issues are: (1) whether the trial court properly applied sec. 971.175, Stats.; (2) whether the state violated Schultz’s right against self-incrimination by using his Goodchild testimony for impeachment purposes; (3) whether Schultz was denied effective assistance of counsel; and (4) whether Schultz is entitled to a new trial.1 We resolve all issues against Schultz and affirm.
FACTS
Schultz was convicted of the first-degree murder of his wife, Nancy Schultz. Police had found Schultz lying unconscious next to his dead wife in their carbon monoxide-filled garage. An autopsy revealed that although carbon monoxide poisoning had caused Nancy Schultz’s death, before death she had received at least one blow to the head with a blunt object which may have rendered her unconscious. Schultz’s five-year-old daughter testified that her mother and father had been fighting in the garage.
*373 Sec. 971.175, Stats.
Schultz pled not guilty and not guilty by reason of mental disease or defect and was tried pursuant to sec. 971.175, Stats., which provides for a bifurcated trial in such situations. After the first phase, the jury found him guilty of first-degree murder. Schultz withdrew his plea of not guilty by reason of mental disease or defect, and the trial court sentenced him to life imprisonment.
Schultz argues that the trial court followed the procedure outlined in sec. 971.175, Stats., and thereby denied him due process of law and equal protection of the laws. Since this question involves the interpretation of a statute, we review it de novo. City of Waukesha v. Salbashian, 128 Wis. 2d 334, 347, 382 N.W.2d 52, 56 (1986).
Section 971.175, Stats., provides:
When a defendant couples a plea of not guilty with a plea of not guilty by reason of mental disease or defect, there shall be a separation of the issues with a sequential order of proof before the same jury in a continuous trial. The guilt issue shall be heard first and then the issue of the defendant’s mental responsibility. The jury shall be informed of the 2 pleas and that a verdict will be taken upon the plea of not guilty before the introduction of evidence on the plea of not guilty by reason of mental disease or defect. This section does not apply to cases tried before the court without a jury.
We interpret this provision to require that both phases must be tried before a single jury, and that the jury must be informed of the insanity plea before the guilt phase of the trial. Schultz claims this deprives him of the presumption of innocence. In State v. Sarinske, 91 Wis. 2d 14, 29-30, 280 N.W.2d 725, 732 *374(1979), the supreme court rejected this argument, asserting that a properly instructed jury will follow instructions even where there are inconsistent pleas. Schultz’s problem is similar to the “insoluble problem” of a defendant who asserts that a homicide was accidental or justified, i.e., that of “maintaining the latter stance without seeming to concede he did the killing.” Id. at 30-31, 280 N.W.2d at 732-33. Like such defendant, Schultz is not entitled to a separate jury for each inconsistent defense he raises. Id. at 31, 280 N.W.2d at 733.
Schultz argues that Sarinske implied that where a defendant presents a substantial defense on the merits or where substantial prejudice would result from the same jury trying both issues, a defendant should be entitled to a second jury on the issue of his or her mental responsibility. We need not address these assertions because the essence of Schultz’s argument on this issue is that the trial court prejudiced the jury against him by following the mandate in sec. 971.175, Stats. The trial court found otherwise.
The trial court granted Schultz’s motion for individual and sequestered voir dire of potential jurors. At Schultz’s post-conviction hearing, the trial court found that the “thorough searching voir dire process” on this issue cured any possibility of jury prejudice. The court noted that any “juror that had any problems or any difficulty” with the two pleas was “discovered and was, on motion, then released.” On appeal, Schultz does not claim that this finding is clearly erroneous, but merely asserts that the jury must have been prejudiced against him, thereby denying him the presumption of innocence. Because Schultz shows no error we affirm as to this issue.
*375 Goodchild Testimony
Schultz claims that the trial court violated his fifth amendment right against self-incrimination by allowing the state to impeach him with his Goodchild2 testimony. Where the historical facts of a case are undisputed, we review the constitutional significance of those facts de novo. State v. Stevens, 123 Wis. 2d 303, 313-14, 367 N.W.2d 788, 794, cert. denied, 474 U.S. 852 (1985).
Schultz had requested a Goodchild hearing on his motion to suppress statements he made to police because he claimed he had not knowingly waived his Miranda rights. During the hearing, Schultz claimed he had no recall of the events of November 19, 1985, the date of his wife’s death. The trial court concluded that Schultz had knowingly and understandingly waived his right to remain silent, and denied his motion to suppress. At trial, the court prohibited the state from using the Goodchild testimony in its case-in-chief. After the state rested, Schultz testified that he remembered the events of November 19,1985. On cross-examination, the state impeached Schultz with his Goodchild testimony.
In Wold v. State, 57 Wis. 2d 344, 356, 204 N.W.2d 482, 490 (1973), our supreme court held that “evidence excluded on direct should not be used for impeachment unless the accused takes the stand and testifies to matters directly contrary to what is in the excluded statement.” The exception to this rule is if the excluded statement is untrustworthy, i.e., coerced or. involuntary. *376Id. at 355, 204 N.W.2d at 489-90. Schultz does not claim that his Goodchild testimony was coerced or involuntary. However, he claims that Simmons v. United States, 390 U.S. 377 (1968), bans any state use of his suppression hearing testimony. We disagree.
In Simmons, the police found two suitcases containing crime evidence after a warrantless search of a defendant’s mother’s house. 390 U.S. at 380. To establish standing for his suppression motion, a defendant asserted that one of the suitcases was similar to a suitcase he owned, and that he owned the clothing found inside it. Id. at 381. The trial court denied his suppression motion, and the court allowed the state to use his suppression motion testimony against him at trial. Id.
The United States Supreme Court reversed. It noted that the suitcase was strong evidence against the defendant, and that the government might have found it difficult to prove it was the defendant’s without defendant’s suppression motion testimony. Simmons, 390 U.S. at 391. The Court also noted that the dilemma the defendant faces “is most extreme in prosecutions for possessory crimes, for then the testimony required for standing itself proves an element of the offense.” Id. The Court reasoned that “a defendant with a substantial claim for the exclusion of evidence may conclude that the admission of the evidence, together with the Government’s proof linking it to him, is preferable to risking the admission of his own testimony connecting himself with the seized evidence.” Id. at 393.
The Court concluded that a defendant should not be “obliged either to give up what he believed, with advice of counsel, to be a valid Fourth Amendment claim or, in legal effect, to waive his Fifth Amendment privilege against self-incrimination.” Simmons, 390 *377U.S. at 394. The Court held that “when a defendant testifies in support of a motion to suppress evidence on Fourth Amendment grounds, his testimony may not thereafter be admitted against him at trial on the issue of guilt unless he makes no objection.” Id.
In Harris v. New York, 401 U.S. 222 (1971), the state used some of the defendant’s statements taken in violation of Miranda v. Arizona, 384 U.S. 436 (1966), to impeach defendant’s testimony. 401 U.S. at 223. The Court upheld this practice. “Having voluntarily taken the stand, petitioner was under an obligation to speak truthfully and accurately, and the prosecution here did no more than utilize the traditional truth-testing devices of the adversary process.” Id. at 225 (footnote omitted).
Here, the state did not use Schultz’s Goodchild testimony for proof of guilt, but to impeach him with his prior statement that he did not remember what happened the day of his wife’s death. Schultz waived his right against self-incrimination when he testified in his own defense at trial. The state’s use of Schultz’s prior testimony to impeach him was allowable under Wold, 57 Wis. 2d at 356, 204 N.W.2d at 490. We affirm as to this issue.
Ineffective Assistance of Counsel
Schultz claims that he was denied effective assistance of counsel in violation of the sixth amendment to the U. S. Constitution. Whether counsel’s actions constitute effective assistance of counsel is a mixed question of law and fact. State v. Johnson, 133 Wis. 2d 207, 216, 395 N.W.2d 176, 181 (1986). The trial court’s *378findings of fact regarding what happened will be upheld unless clearly erroneous. Id. Whether an attorney’s behavior was deficient and whether it prejudiced the defendant, depriving him or her of effective assistance of counsel, are questions of law which we review de novo. State v. Pitsch, 124 Wis. 2d 628, 634, 369 N.W.2d 711, 715 (1985). We use the two-prong test of Strickland v. Washington, 466 U.S. 668, 687 (1984) to assess an ineffective assistance of counsel claim. Normally, we first determine whether counsel’s performance was deficient, and, if we conclude it was, we then decide whether the deficient performance prejudiced the defendant. Johnson, 133 Wis. 2d 216-17, 395 N.W.2d at 181.
Schultz must first identify those acts or omissions he claims were not the result of reasonable professional judgment. Johnson, 133 Wis. 2d at 217, 395 N.W.2d at 181. The court must then judge whether, considering all of the circumstances, those acts or omissions were outside the range of professionally competent assistance. Id. The court, in making its judgment, should remember that counsel’s function is to make the adversary testing process succeed in the particular case. Id. There is a strong presumption that counsel adequately assisted a defendant and that counsel always exercised reasonable professional judgment in deciding significant trial issues. Id. In addition,
there is no reason for a court deciding an ineffective assistance claim to approach the inquiry in the same order or even to address both components of the inquiry if the defendant makes an insufficient showing on one. ... If it is easier to dispose of an ineffectiveness claim on the ground of lack of sufficient prejudice, which we expect will often be so, that course should be followed.
*379Strickland, 466 U.S. at 697.
Schultz cites the following instances of what he claims demonstrates ineffective assistance of counsel:3
(1) that trial counsel failed to properly investigate his case by failing to have the furnace motor tested;
(2) that trial counsel failed to advise defendant properly about the ramifications of his not guilty plea and his not guilty by reason of mental disease or defect plea.
Schultz claims that his trial counsel failed to investigate his theory of the furnace motor.4 He asserts *380that had his trial counsel done so, this would have bolstered his credibility as a witness in his own defense. He concludes that his trial counsel were ineffective by not investigating this issue, and that such ineffectiveness prejudiced his defense. We disagree.
[A] particular decision not to investigate must be directly assessed for reasonableness in all the circumstances, applying a heavy measure of deference to counsel’s judgments.
The reasonableness of counsel’s actions may be determined or substantially influenced by the defendant’s own statements or actions.
Strickland, 466 U.S. at 691. Schultz’s trial counsel testified that they did not investigate the furnace fan theory because they concluded the issue had nothing to do with what they had identified as the two critical factors of the trial: (1) explaining how Schultz’s wife got the two bruises on her head; and (2) explaining Schultz’s daughter’s testimony that “mommy and *381daddy fighted.” We conclude counsels’ decision not to investigate was reasonable, and thus not deficient performance.
Regarding the alleged failure to advise Schultz properly about his apparently inconsistent pleas, we need not decide whether counsel’s actions amounted to deficient representation.5 What Schultz is ultimately claiming is that his inconsistent pleas prejudiced the jury against him. However, as we have previously noted, the trial court found that during the extensive individual voir dire, any jurors indicating such prejudice were removed. Therefore, even if there were deficient representation on this matter, it did not prejudice the jury or the result, and reversal is not required. Strickland, 466 U.S. at 691.
Wisconsin Constitutional Claim
Schultz also claims that he was denied his right to effective assistance of counsel in violation of Wis. Const, art. I, sec. 7. Although he implies that the state constitution provides criminal defendants more protection than the sixth amendment to the federal constitution, he acknowledges that no Wisconsin Supreme Court cases have decided this issue. He also notes that certain Wisconsin Court of Appeals decisions since Strickland have stated different tests to determine ineffectiveness of counsel. However, none of these cases held that an ineffectiveness analysis under Wis. Const, art. I, sec. 7, is stricter than a similar analysis under the sixth amendment to the U.S. Constitution.
*382Though Schultz argues that Wis. Const, art. I, sec. 7, provides a stricter standard that the sixth amendment to the U. S. Constitution, he has not fulfilled the requirements laid out in Pitsch, 124 Wis. 2d at 646, 369 N.W.2d at 721:
Although both the state and the defendant cite art. I, sec. 7 of the Wisconsin Constitution, neither party develops an argument based on the state constitution. The parties provide no history of the provision, which might enable us to determine the extent to which it was or was not intended to parallel the federal constitution; they provide no discussion of case law interpreting art. I, sec. 7; they provide no discussion of the purpose or application of the provision in terms of guaranteeing the quality of the legal profession or guaranteeing the reliability of the outcome in a given case.
The Pitsch court rejected references to prior Wisconsin cases addressing ineffectiveness of counsel claims either because the court in those cases relied upon the federal constitution or because it was unclear which constitution the court relied upon. Id. at 647, 369 N.W.2d at 721. Since Schultz’s argument fails to fulfill the Pitsch requirements, we do not consider his claim based on the Wisconsin Constitution.
Request for New Trial
Schultz requests a new trial in the interest of justice pursuant to sec. 752.35, Stats., because it is probable that justice has miscarried due to the numerous errors by the court and his trial counsel. However, Schultz has at most shown harmless error which had no effect on the trial’s result. It does not appear that a *383retrial under optimum circumstances would produce a different result. State v. Friedrich, 135 Wis. 2d 1, 35, 398 N.W.2d 763, 778 (1987). We deny Schultz’s request.
By the Court. — Judgment and order affirmed.
Schultz also argues that the first court commissioner’s dismissal of the complaint deprived the trial court of personal jurisdiction over him. Schultz never objected to the trial court’s personal jurisdiction on this ground.
Below, Schultz’s jurisdictional arguments were based on motions to dismiss an allegedly illegal arrest and the insufficiency of both the original and amended complaints. The court ruled against him on both these motions, and those rulings are not challenged to appeal. Schultz argues he preserved his objection to the trial court’s personal jurisdiction over him. However, because he did not object on the specific grounds he now raises on appeal, he did not preserve this issue for appellate review, and therefore we do not address it. Compare Holmes v. State, 76 Wis. 2d 259, 271, 251 N.W.2d 56, 62 (1977) (party may appeal an adverse ruling on an objection to evidence only upon the specific grounds raised below).
State ex rel. Goodchild v. Burke, 27 Wis. 2d 244, 133 N.W.2d 753 (1965), cert. denied, 384 U.S. 1017 (1966), established a hearing procedure to determine the voluntariness of a defendant’s confession.
Although Schultz claims other instances of ineffectiveness of counsel, we do not address them. A convicted defendant must identify to the trial court those “acts or omissions of counsel that are alleged not to have been the result of reasonable professional judgment.” Strickland, 466 U.S. at 690. For the first time on appeal, Schultz argues that his counsel did not properly advise him regarding his decision to testify, that they improperly handled videotape evidence and that they had no theory of defense. These issues were not specifically identified by motion or affidavit below and they were not argued in Schultz’s brief to the trial court. The videotape issue was not addressed during oral argument, and the other two issues were mentioned in a passing manner on rebuttal. We conclude that Schultz failed to raise and argue these issues below, and we do not address them further on appeal. State v. Hahn, 132 Wis. 2d 351, 361, 392 N.W.2d 464, 468 (Ct. App. 1986).
Schultz’s theory on the furnace motor needs explanation. At issue is why a certain fuse, which controlled the automatic garage door opener, the garage lights and the furnace fan motor, was found unscrewed at the time of the murder. At trial, the prosecution implied that Schultz had unscrewed the fuse, thereby removing power from the garage light and door opener, in order to prepare the garage to kill his wife. The prosecutor’s theory was that Schultz started the car in his garage in order to fill the garage with carbon monoxide. He then brought his wife into the dark garage, the atmosphere of which could not be cleared because the garage door *380opener had no power. He then struck her on the head with a blunt object to render her unconscious in order to keep her from escaping the garage, and so she would die from carbon monoxide poisoning. Schultz testified at trial that he had unscrewed the fuse in order to turn off a furnace fan motor, which would overheat. The prosecution took issue with this, arguing that if this were true, why had the defense not brought in an expert to so testify?
At the postconviction hearing, Schultz’s trial counsel testified that Schultz never told them his theory of the furnace fan until April 2,1986, five days before trial, and that he never asked them to investigate. They also testified, as did Schultz, that Schultz had previously told them that he had unscrewed the fuse for security reasons. This was because he had valuable tools and a car in the garage, and he was not there often. The trial court found Schultz’s trial counsels’ testimony “totally credible.”
We do note that at the postconviction hearing, Schultz’s trial counsel testified that they did advise Schultz completely on his pleas. The trial court found trial counsels’ testimony totally credible.