The state appeals a judgment granting petitioner post-conviction relief. We affirm.
The petition alleges that petitioner’s conviction for criminal nonsupport, ORS 163.555, is unlawful, because the district attorney had excused one of the grand jurors from attendance at the session in which evidence against petitioner was presented and an indictment returned against him.1 The post-conviction court held that, because Article VII (amended), section 5(2), of the Oregon Constitution2 mandates a seven-person grand jury, the district attorney’s action violated the Constitution and rendered the indictment void. ORS 138.530(1).
The state contends that only five jurors need be present at a meeting of the grand jury and that those five may return an indictment, if they unanimously concur. To support that contention, it relies on the Oregon Constitution and ORS 132.360,3 which both provide that only five grand jurors need to concur to return an indictment. In addition, it notes that ORS 132.110 provides, in part:
“After the formation of the grand jury and before it is discharged, the court may:
“(1) Discharge a grand juror * * *
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“(3) Allow at least five grand jurors to proceed upon good cause shown.” (Emphasis supplied.)
*282Because six jurors were at the session when the indictment was returned, the state argues that the district attorney’s conduct was simply a violation of ORS 132.110(3) and not a constitutional violation requiring that petitioner’s conviction be set aside.
In State v. Campbell, 306 Or 157, 162, 759 P2d 1040 (1988), the court instructed that we “may not reach a state constitutional issue if a claim is fully satisfied under other provisions of state law.” Because this is a post-conviction proceeding, petitioner is entitled to relief only if the trial court lacked jurisdiction over his offense or if he was deprived of a constitutional right. ORS 138.530.4 In State v. Witt, 33 Or 594, 596, 55 P1053 (1899), the court clarified that a statutory violation relating to the formation of a grand jury does not deprive a court of jurisdiction, unless the violation results in an unconstitutionally constituted grand jury. Accord State v. Gortmaker, 295 Or 505, 522, 668 P2d 354 (1983). Consequently, petitioner is entitled to post-conviction relief only if the violation of ORS 132.110(3) also constituted a constitutional violation.5
The express language of Article VII (amended), section 5(2), requires that a grand jury consist of seven persons, but permits five of them to find an indictment. The genesis *283and purpose of that nonunanimity requirement is uncertain.6 However, it appears to have a basis like the requirement that 10 of 12 petit jurors return a verdict in a criminal trial. Or Const, Art I, § 11. That is intended to permit the expression and consideration of minority viewpoints but, through the nonunanimity requirement, precludes a minority from thwarting an otherwise justifiable indictment. See Apodaca v. Oregon, 406 US 404, 413, 92 S Ct 1628, 32 L Ed 2d 184 (1972).
If a grand or petit jury proceeds with fewer than the requisite number of members, the balanced view that the deliberative process promotes may not be achieved. A person omitted from a panel may have been able to express a viewpoint that would have persuaded the other members of the jury to a particular position or to evaluate a critical part of a case with more scrutiny. We cannot say that a grand jury panel of five or six jurors would always reach the same conclusion as if there had been seven members in attendance.
By requiring that 12 petit jurors hear all of the evidence, Article I, section 11, promotes a deliberative process that permits expression and consideration of minority viewpoints, thereby insulating an accused from biased or overzealous prosecution. That right is a significant right that a defendant must affirmatively waive. State v. Lutz, 306 Or 499, 502, 760 P2d 249 (1988). Because Article VII (amended), section 5(2), promotes the same deliberative process at the grand jury level, it is also a significant right. Consequently, we conclude that it mandates that seven grand jurors hear and consider all of the evidence presented before a valid indictment can be found.
In State v. Lawrence, 12 Or 297, 7 P 116 (1885), the court concluded:
“[I]t is the constitutional right of a defendant accused of a crime to demand that the indictment shall be found by a grand jury selected only as provided in the Constitution.” 12 Or at 300.
*284Because only six grand jurors heard the evidence in petitioner’s case, he was entitled to dismissal of the indictment.7
Affirmed.
The post-conviction court rejected petitioner’s due process claims under Article I, section 10, of the Oregon Constitution and the Fifth and Fourteenth Amendments to the United States Constitution. Petitioner does not assign error to those rulings on appeal.
Article VII (amended), section 5(2), provides:
“A grand jury shall consist of seven jurors chosen by lot from the whole number of jurors in attendance at the court, five of whom must concur to find an indictment.”
The constitutional provision is reflected in ORS 132.360:
“A grand jury may indict or present to the court for instruction as provided in ORS 132.370, with the concurrence of five of its members, if at least five jurors voting for indictment or presentment heard all the testimony relating to the person indicted or facts presented.”
ORS 138.530 provides, in part:
“(1) Post-conviction relief pursuant to ORS 138.510 to 138.680 shall be granted by the court when one or more of the following grounds is established by the petitioner:
“(a) A substantial denial in the proceedings resulting in petitioner’s conviction * * * of petitioner’s rights under the Constitution of the United States, or under the Constitution of the State of Oregon, or both, and which denial rendered the conviction void.
“(b) Lack of jurisdiction of the court to impose the judgment rendered upon petitioner’s conviction.”
In State v. Gortmaker, 295 Or 505, 510, 668 P2d 354 (1983), the court said:
“Article VII (Amended), Section 5, cannot be read as reserving to the legislature the power to enact statutes which serve to prevent constitutional challenges to grand jury proceedings.”
Consequently, a defendant can challenge the constitutionality of grand jury proceedings, even in the absence of a statutory violation. Because the issue here is whether the constitution was violated, we do not consider those cases that address violations of statutes regulating grand jury proceedings. See, e.g., State v. Bock, 49 Or 25, 88 P 318 (1907).
For a discussion of the history of the grand jury and Oregon’s constitutional provisions concerning that institution, see State v. Gortmaker, supra, 295 Or at 510.
We agree with the dissent that whether Article VII (amended), section 5(2), imposes a requirement that seven grand jurors hear and consider all of the evidence before deciding whether to return an indictment is a question of the drafter’s intent. However, unlike the dissent, I believe that the intent may be discerned not only from the plain language of that provision, but also from an examination of the history of the institution itself and of the constitutional provision. That is precisely the analytical process that the court used in State v. Gortmaker, supra. Moreover, in that case, the court indicated that it is appropriate to consider whether an act is prohibited by Article VII (amended), section 5(2), by evaluating whether a defendant could be prejudiced by that act. See State v. Gortmaker, 295 Or at 519.
We have already discussed how the absence of one or two grand jurors from a panel could prejudice a defendant. Because that prejudice would be eliminated by reading Article VII (amended), section 5(2), to mean exactly what it says, we reject the dissent’s contention that we cannot hold that the drafters of the Oregon Constitution intended a provision of that document to mean a certain thing in the absence of compelling evidence. Although the policy judgment was made by the framers of the Constitution, we believe that that policy judgment can be discerned from the language and spirit of Article VII (amended), section 5(2).