JUSTICE KIRSHBAUM delivered the Opinion of the Court.

Appellant Mack Willie Thomas was convicted of two counts of sexual assault on a child on August 26, 1986. On appeal, the court of appeals vacated the convictions and remanded the case for further proceedings with respect to the admissibility of hearsay evidence from two child witnesses. People v. Thomas, 770 P.2d 1324 (Colo.App. 1988). On certiorari review, we reversed the court of appeals' judgment and reinstated the convictions. Thomas v. People, 803 P.2d 144 (Colo. 1990).

On September 27, 1991, Thomas filed a Crim. P. 35(c) motion to vacate his convictions on the ground of ineffective assistance of counsel — an issue not raised in his earlier appeal. The trial court denied the motion on the ground that section 16-5-402(3), 8A C.R.S. (1986), prohibited the filing thereof. Having transferred this appeal to this court from the court of appeals pursuant to section 13-4-102(1)(b) and 13-4-110(1)(a), 6A C.R.S. (1987), to review the propriety of the trial court's ruling, we reverse and remand the case with directions to the trial court to conduct further proceedings.

I

In May of 1986, some three and one-half months prior to the commencement of trial in this case, Thomas was convicted of a separate and unrelated charge of sexual assault on a child. Although affirmed on direct appeal, People v. Thomas, No. 86CA1007 (Colo.App. May 25, 1989) (not selected for official publication), cert. denied, No. 89SC396 (Colo. Sept. 18, 1989), the judgment of conviction in that case was ultimately vacated when, at the conclusion of a Crim. P. 35(c) proceeding, the trial court determined that Thomas' constitutional right to effective assistance of counsel had been violated. The prosecution elected not to re-file that case.

On August 20, 1992, in the instant case, Thomas filed a motion for new trial or reduction of sentence, pursuant to Crim. P. 35(b). He subsequently filed a motion for new trial pursuant to Crim. P. 35(c), asserting, inter alia, a denial of his right to effective assistance of counsel. In an affidavit filed in support of his Crim. P. 35(c) motion, Thomas avers that although he informed his trial attorney that he, Thomas, desired to testify at trial, he did not do so because of the probability that his credibility would be impeached by reference to the prior conviction. He also avers that his trial attorney advised Thomas that he "had a strong case of ineffective assistance of counsel" with respect to the prior conviction; that Thomas questioned how the "bad" conviction could be used against him, especially when the prior case was on appeal; and that the attorney responded to these inquiries by stating that the prosecutor "would use it to impeach [Thomas]." Thomas' trial attorney did not attempt to suppress the prior conviction.

The trial court denied Thomas' Crim. P. 35(c) motion without conducting an evidentiary hearing on the merits thereof. The trial court initially held that the provisions of section 16-5-402(3) prohibited consideration of the motion. Alternatively, the trial court ruled that the decision of Thomas' trial attorney to refrain from filing a motion to suppress the prior conviction represented a strategic decision and did not constitute ineffective assistance of counsel. Thomas appealed, asserting that the provisions of section 16-5-402(3) were not applicable to his Crim. P. 35(c) motion; that if the statute did govern, it violated several federal and Colorado constitutional principles on its face and as applied; and that Thomas was entitled to an evidentiary hearing on his motion.

II

Section 16-5-402, 8A C.R.S. (1986), contains the following pertinent provisions:

Limitation for collateral attack upon trial judgment. (1) Except as otherwise provided in subsection (2) of this section, no person who has been convicted under a criminal statute of this or any other state of the United States shall collaterally attack the validity of that conviction unless such attack is commenced within the applicable time period, as provided in this subsection (1), following the date of said conviction:

All class 1 felonies: No limit

All other felonies: Three years

. . . .

(2) In recognition of the difficulties attending the litigation of stale claims and the potential for frustrating various statutory provisions directed at repeat offenders, former offenders, and habitual offenders, the only exceptions to the time limitations specified in subsection (1) of this section shall be:

(a) A case in which the court entering judgment of conviction did not have jurisdiction over the subject matter of the alleged offense;

(b) A case in which the court entering judgment of conviction did not have jurisdiction over the person of the defendant;

(c) Where the court hearing the collateral attack finds by a preponderance of the evidence that the failure to seek relief within the applicable time period was caused by an adjudication of incompetence or by commitment of the defendant to an institution for treatment as a mentally ill person; or

(d) Where the court hearing the collateral attack finds that the failure to seek relief within the applicable time period was the result of circumstances amounting to justifiable excuse or excusable neglect.

(3) If the judgment of conviction to which any collateral attack is directed was sustained upon review by a court of appellate jurisdiction in the state where the judgment was entered, no collateral attack on such judgment shall be permitted whether commenced within or outside the time limitations set forth in subsection (1) of this section, unless said collateral attack is based upon an opinion of the court of last resort subsequently announced in the state where the judgment was entered, which opinion is given retroactive effect in a manner invalidating the conviction.

§ 16-5-402, 8A C.R.S. (1986). The General Assembly has thus determined the availability of collateral attacks with respect to two classes of criminal cases. Sections 16-5-402(1) and (2) establish a time limit within which collateral attacks may be asserted in cases where no appeal has been taken or no final decision of an appeal has been rendered. Section 16-5-402(3) addresses criminal cases which have been unsuccessfully appealed and prohibits any collateral attack of a conviction affirmed on appeal unless the conviction is no longer valid because of a retroactively applicable appellate decision in the state in which the conviction was obtained.

When construing statutory provisions, our responsibility is to effectuate the intent of the General Assembly. E.g., Homestake Enters., Inc. v. Oliver, 817 P.2d 979, 981-82 (Colo. 1991); Sigman v. Seafood Ltd. Partnership I, 817 P.2d 527, 530 (Colo. 1991). When the statutory language itself does not readily reveal that intent, certain principles of statutory construction guide us. When possible, statutes are to be construed in such manner as to avoid questions of their constitutional validity. Perry Park Water Sanitation Dist. v. Cordillera Corp., 818 P.2d 728, 732 (Colo. 1991); People v. Lybarger, 700 P.2d 910, 915 (Colo. 1985). However, we must give full effect to the language used by the General Assembly even if to do so results in a determination that the statute violates constitutional criteria. People v. New Horizons, Inc., 200 Colo. 377, 383, 616 P.2d 106, 110 (1980).

In People v. Germany, 674 P.2d 345, 351-54 (Colo. 1983), we held that the predecessor of current section 16-5-402(1) violated constitutional guarantees of due process of law by prohibiting the filing of collateral attacks on judgments of conviction outside the statutorily specified time limits even if the failure to act within those limits resulted from justifiable excuse or excusable neglect. The General Assembly subsequently amended section 16-5-402(2) to permit collateral attacks outside the statutory limitations periods provided by section 16-5-402(1) when the delay resulted from justifiable excuse or excusable neglect. Ch. 117, sec. 1, § 16-5-402(2)(d), 1984 Sess. Laws 486, 486. Although in Germany we were not required to consider the constitutionality of section 16-5-402(3), we did comment on this section as follows:

It necessarily follows that if a "court of last resort" does not expressly decide the retroactive application of a newly promulgated constitutional rule, subsection (3) would prohibit the defendant from collaterally challenging a prior conviction even though his challenge is based upon a colorable claim that the new rule is such that retroactive application is constitutionally mandated.

Id. at 353 (footnote omitted). We also observed that the provisions of subsection (3) imposed even greater limitations on collateral attacks than the provisions of subsections (1) and (2). Id. at 351. While noting the state's legitimate interest in the finality of convictions, we emphasized the importance of assuring that defendants are afforded meaningful opportunities to challenge allegedly unconstitutional convictions. Id. at 349-50.

In establishing time frames within which such issues must be raised, the General Assembly recognized the importance of upholding the finality of judgments and furthering the policies embodied in enhanced penalty legislation directed at recidivists. § 16-5-402(2), 8A C.R.S. (1986); People v. Wiedemer, 852 P.2d 424, 436 (Colo. 1993). As amended, sections 16-5-402(1) and -402(2) also recognize the necessity of affording persons the right to post-conviction judicial consideration of constitutional issues allegedly affecting the validity of judgments of conviction. However, section 16-5-402(3) for all practical purposes eliminates the ability of a person who has appealed a conviction to challenge its constitutionality even though no court has considered the constitutional issue raised.

An examination of the structure and language of section 16-5-402 compels the conclusion that the statute achieves this draconian result. Section 16-5-402(1) limits the time in which a person convicted under a criminal statute of this or any other state may bring a collateral attack of that conviction. Section 16-5-402(2)(d), as amended subsequent to our decision in Germany, 674 P.2d 345, provides an exception to these time limitations if a convicted person's failure to collaterally challenge the constitutionality of a conviction within the limitations period was the result of circumstances amounting to justifiable excuse or excusable neglect. Section 16-5-402(2) expressly limits this exception to the time period provisions established by section 16-5-402(1).

Section 16-5-402(3) contains no limitations period. The only exception to its complete ban of post-conviction collateral attacks in cases that have been appealed is the proviso that such attacks may be permitted if a "court of last resort" in the state where the judgment was entered announces a retroactively effective decision that would invalidate the conviction. § 16-5-402(3). See § 18-1-410(f), 8B C.R.S. (1986), and Crim. P. 35(c)(1) (authorizing post-conviction relief on the grounds of a significant, retroactively applicable change in the law only while the appeal is pending). The statute refers only to criminal cases and proceedings, not to issues. Thus, for purposes of section 16-5-402(3), all post-conviction remedies, including habeas corpus actions as well as Crim. P. 35(c) proceedings, are barred without regard to the particular issues raised or not raised in the initial appeal. As we indicated in Germany, the provisions of section 16-5-402(3) are unduly restrictive. The People suggest that section 16-5-402(3) may be construed to incorporate the justifiable excuse or excusable neglect standard established by section 16-5-402(2)(d). Such construction not only strains the text of section 16-5-402(3) beyond tolerable limits, but ignores the specific language of section 16-5-402(2) limiting the applicability of section 16-5-402(2)(d) to the limitations period established in section 16-5-402(1). Courts may not assume a legislative intent which would vary the words used by the General Assembly. Jones v. People, 155 Colo. 148, 154, 393 P.2d 366, 369 (1964). Furthermore, as previously noted, the difficulties created by section 16-5-402(3) involve consideration of particular issues in cases, not simply cases or proceedings in general. The statute addresses questions of cases and procedures.

The People also suggest that the provisions of section 16-5-402(3) might be harmonized with the provisions of section 18-1-410. However, in People v. Heitzman, 852 P.2d 443 (Colo. 1993), we concluded that these statutes conflict and that, as the more recently adopted legislation, section 16-5-402(3) prevails. Id. at 446-47. We adhere to that view.

Thomas asserts that the statute does not apply to him because his Crim. P. 35(c) motion does not constitute a collateral attack. We rejected identical arguments in Wiedemer, 852 P.2d at 430, and in Heitzman, 852 P.2d at 466.

As applicable to Thomas, section 16-5-402(3) prevents any consideration of his claim of constitutionally ineffective assistance of counsel because he unsuccessfully appealed his conviction. However, questions of ineffective assistance of trial counsel may well not become apparent until after the appellate process is concluded, most particularly when trial counsel serves as counsel on appeal. Section 16-5-402(3) also extends to cases otherwise subject to reconsideration on the basis of newly discovered evidence. See Crim. P. 35(c)(2)(V).

The People argue in the alternative that section 16-5-402(3) should be construed to permit post-conviction collateral review of convictions affirmed on appeal if the constitutional issue asserted could not reasonably have been raised in the earlier appeal. Such construction, it is contended, would harmonize the provisions of sections 16-5-402(3) and 18-1-410. The language of section 16-5-402(3) does not permit such refinement, however. Furthermore, as the People recognize, this proposed construction would in all probability prohibit Thomas and others similarly situated from pursuing claims of ineffective assistance of trial counsel if they were represented by separate counsel on appeal.

In view of the language of section 16-5-402(3) and our conclusion that it applies to Thomas, we address Thomas' arguments that the statute violates federal and state constitutional provisions. Thomas challenges the constitutionality of section 16-5-402(3) on three grounds: that the statute violates the due process guarantees of the federal and state constitutions; that it effects an unconstitutional suspension of the writ of habeas corpus; and that the statute violates the separation of powers doctrine. We agree with his first argument, and therefore need not address the other two issues.

While it has been suggested that the Due Process Clause of the federal constitution guarantees neither the right to appeal a judgment of conviction, Griffin v. Illinois, 351 U.S. 12, 18 (1956) (plurality opinion), nor the right to seek post-conviction relief, United States v. MacCollom, 426 U.S. 317, 323 (1976) (plurality opinion), but see Colo. Const. Art. VI, sec. 2(2) (providing a right to appeal all final state court trial judgments), all states and the federal government have provided rights to appeal criminal convictions and to pursue post-conviction relief. Whether by writ of habeas corpus, coram nobis, statute or court rule, every state provides a mechanism to challenge convictions on constitutional grounds, unhindered by the procedural obstacles created by the ancient forms of the common law writs.

While many, if not most, constitutional claims which could be brought in a Crim. P. 35(c) motion could also be brought in a direct appeal, this court has expressed a preference for having ineffective assistance of counsel claims brought in Crim. P. 35(c) proceedings. Cummings v. People, 785 P.2d 920, 927-28 (Colo. 1990) (Vollack, J., concurring in part and dissenting in part); Stone v. People, 174 Colo. 504, 512, 485 P.2d 495, 498-99 (1971). Such procedure promotes judicial economy because the conviction may be overturned in the course of the direct appeal. Furthermore, in the context of ineffective assistance of counsel claims, a trial court is positioned to hear and evaluate evidence as necessary. See Cummings, 785 P.2d at 925. In cases where the ineffective assistance of counsel claim can purportedly be shown on the record, a proper record on appeal may still require explanations by trial counsel about alleged incompetent acts or omissions, or expert testimony as to the requisite standard of care in the applicable legal community.

Section 16-5-402(3) in effect would preclude claims for ineffective assistance of appellate counsel, as well as claims that either trial counsel or appellate counsel was ineffective because he or she failed on appeal to raise questions about the adequacy of trial counsel representation. By barring such constitutional challenges to convictions simply because the case has been appealed, section 16-5-402(3) violates the Due Process Clause of the Fourteenth Amendment to the United States Constitution and the Due Process Clause of Article II, Section 25, of the Colorado Constitution. Of all persons convicted of crimes in this or any other state, only those who asserted their rights to appeal would be denied the right to challenge an unconstitutional conviction, whether on grounds of newly discovered evidence, the trial court's lack of jurisdiction, or ineffective assistance of counsel. Such deprivation of any ability to challenge the constitutional validity of a conviction denies fundamental fairness to persons convicted of criminal offenses, in violation of the Due Process Clauses of the Fourteenth Amendment to United States Constitution and of Article II, Section 25, of the Colorado Constitution.

III

The trial court concluded that if Thomas is entitled to consideration of his Crim. P. 35(c) motion, his claim of ineffective assistance of counsel should be denied on the basis of the pleadings and the supporting affidavit. Thomas contends that the trial court erred in failing to afford him an evidentiary hearing prior to ruling on his motion. We agree with Thomas' argument in the circumstances of this case.

Under both the fourteenth amendment to the United States Constitution and article II, section 25 of the Colorado Constitution, a criminally accused has a due process right to testify in his own defense. E.g., Faretta v. California, 422 U.S. 806 (1975); Brooks v. Tennessee, 406 U.S. 605 (1972); People v. Curtis, 681 P.2d 504 (Colo. 1984); People v. Myrick, 638 P.2d 34 (Colo. 1981). This right is fundamental, and the opportunity to decide to exercise it freely and without coercive influence is critical to the fairness of the trial itself. Curtis, 681 P.2d at 513-15.

Apodaca v. People, 712 P.2d 467, 472 (Colo. 1985). In Curtis, we emphasized that the defendant's personal participation in the trial process is of value in "legitimat[ing] the outcome of the trial." Curtis, 681 P.2d at 514. We explained our holding there as follows:

Because of the special evidentiary nature of the defendant's testimony, the importance of allowing the defendant to have his say regardless of its effect on the chances of acquittal, and the legitimacy that this opportunity confers upon the outcome of criminal proceedings, we hold that the constitutional right to testify is so fundamental that procedural safeguards are necessary to ensure that the defendant understands the significance of waiver of this right.

Id. (emphasis added). A defendant's decision to exercise or waive the right to testify is undeniably a major facet of all criminal proceedings.

In this case the trial judge determined, in the absence of an evidentiary hearing, that the failure of Thomas' trial attorney to seek suppression of the prior conviction was a strategic decision that did not constitute unreasonable professional conduct. In view of Thomas' averments and the totality of the circumstances surrounding both criminal proceedings, we conclude that the record does not support such conclusion.

In People v. Goff, 187 Colo. 57, 530 P.2d 512 (1974), and People v. Johnson, 192 Colo. 483, 560 P.2d 465 (1977), we held that a conviction could be used to impeach credibility when a motion for new trial was denied by the trial court. See also People v. Jacquez, 196 Colo. 569, 572, 588 P.2d 871, 873-74 (1979) (conviction for purposes of habitual criminal statute effective as of the date judgment of conviction entered by the trial court, including sentence imposed). Thus, the prior judgment of conviction could have been used to impeach Thomas had he taken the stand. The record before us indicates that the motion of Thomas' trial attorney to withdraw in this case occurred prior to sentencing.

Thomas asserted that he would present evidence that his attorney's failure to move to suppress the prior conviction was below the requisite standard of care of a criminal attorney in the requisite legal community. Thomas avers that his attorney never discussed the possibility of obtaining an order suppressing his prior conviction. In these circumstances, we conclude that Thomas is entitled to the evidentiary hearing he requested to permit a full evaluation of his claim of ineffective assistance of counsel. See Strickland v. Washington, 466 U.S. 668, 687-96 (1984); Cummings v. People, 785 P.2d 920, 925 (Colo. 1990).

IV

For the foregoing reasons, the judgment of the trial court is reversed and the case is remanded to that court with directions to conduct an evidentiary hearing to determine the merits of Thomas' claim that the representation afforded him at trial was constitutionally deficient.

JUSTICE ERICKSON dissents, and CHIEF JUSTICE ROVIRA and JUSTICE VOLLACK join in the dissent. JUSTICE VOLLACK dissents, and CHIEF JUSTICE ROVIRA and JUSTICE ERICKSON join in the dissent.