The hour of decision draws near. Some are beginning to discuss the question: Should Illinois convene a constitutional convention?

The Illinois State Chamber of Commerce says no. So, privately, do many elected state officials. The delegates to the 1969-1970 convention see no need. But Patrick Quinn, the driving force behind the 1980 amendment that trimmed the size of the Illinois House, thinks a convention could breathe new life into Illinois politics.

The framers of the state's 1970 Constitution had to wrestle with a 100-year-old document that had become obsolete. To avoid a recurrence, they included a provision requiring that voters be asked at least every 20 years whether a convention should be called. Atty. Gen. Neil F. Hartigan ruled in mid-September that the vote comes in 1988 not 1990.

Lawmakers decided last year that the matter merited some attention. They created a 50-member committee to study the question and make a recommendation to the people. The lawmakers directed the committee to reconvene the delegates to the 1969-1970 convention for their advice.

That reconvening coincided with the 200th anniversary of the signing of the U.S. Constitution. While school children and politicians feted the resiliency of a document that had stood 200 years, the surviving delegates were asked to consider whether after 17 years it was time to change Illinois' Constitution.

After ceremonies at the Old State Capitol, former delegates gathered in conference rooms at the Ramada Renaissance. They reminisced, recalled convention battles and compromises and discussed changes they had expected and not expected. The 60 former delegates took their responsibility seriously and brought a perspective not shared by outsiders. "We sought when we sat down 17 or 18 years ago to write the best constitution we could write in a state as complex politically as Illinois," Samuel C. Witwer, president of the 1969-1970 convention, observed.

Delegates tackled the question of education funding. One of the most hotly debated sentences in the Constitution says, ''The State has the primary responsibility for financing the system of public education.'' Some delegates felt strongly that the provision had been overlooked and that the state should be providing half the money to public schools. Others suggested the provision was working as expected. In one conference 15 former delegates debated the meaning, interrupting and pitching individual ideas as the discussion moved around the table. Sen. Dawn Clark Netsch (D-4, Chicago) began: "Everybody assumes it means 50 percent . . . . It was both a property tax concern and an education concern. . . . What we were really expressing was a very strong affection throughout that convention that it was a state responsibility.''

Malcolm S. Kamin, an attorney and member of the convention's education committee, bolstered Netsch's assessment and commented on the ensuing confusion: "It was intended to mean all things to all people and it clearly meant all things to all people. One person stood up and said I'm supporting it because it means this. And somebody else got up and said I'm supporting it because it doesn't mean that, because it means something else." And as the group moved towards a decision that the section was working as expected, Netsch suggested some benefits. "It has kept the pressure on the legislature which it was intended to do. . . . We are beaten over the head 365 days a year about that very sentence in the Constitution."

Two items came out of the Friday round-table sessions for consideration Saturday by the entire group of returning delegates. The first involved the application of constitutional protections against discrimination contained in the Constitution. Springfield attorney Mary Lee Leahy claimed that court decisions requiring that administrative remedies — namely by the state Department of Human Rights and Human Rights Commission — be exhausted before the courts could be used, had made the section worthless. Delegates voted to table a resolution saying the sections had not fulfilled their expectations. However, they chose to side with Auditor General Robert G. Cronson in his battle with the Supreme Court over auditing of fees paid by attorneys for licenses to practice law. Cronson's office was a creation of the 1970 Constitution, and the delegates expressed their opinion that Cronson should audit the fees.

The key piece of work done on September 19 was passage of a resolution stating the delegates' support of the document: "We are generally well pleased with the product of our labors of 1969 and 1970 and believe that such changes as may be desirable can be handled by legislation, interpretation or the amendment process." A single delegate opposed the resolution. David Kenney suggested that needed changes discussed freely by delegates were too significant to be accomplished by the amendment process. "I do not have confidence that a broad range of significant changes, or even one significant change, will be accomplished by piecemeal amendment."

The reconvening was the centerpiece and the first step in the ongoing effort to stir up interest in next November's vote. Also scheduled by the Committee of 50 were public hearings across Illinois, seminars at Illinois State University and a concluding session of the Committee of 50 at Northern Illinois University. Like many state operations this year, the effort ran into fiscal problems. Funding for the effort was slashed, and the $20,000 spent on the reconvening left the coffers nearly empty. The committee was looking for ways to cut expenses and seeking money from other sources to put on the seminars and final assembly.

But the reconvening has started to spark interest. Robert Creamer, executive director of the Illinois Public Action Council, says his board may take up the question soon. Some issues, like electing members of the Illinois Commerce Commission, could be dealt with by a convention. But gains must be weighed against possible losses from a new convention, he warns. ''The right wing is pretty well organized.'' The notion that conservatives could control a constitutional convention does not worry Pat Quinn. "I think the voters are a lot more level headed about that than politicians and commentators give them credit for," he says. Quinn believes a convention would include a cross section of delegates with more moderates than either conservatives or liberals.

And, Quinn believes, such a convention would be an opportunity to bring a breath of fresh air to the process. "I think the process of a new convention could reinvigorate Illinois politics," Quinn says. Issues likely to spark a yes vote are ethical issues like those raised by the federal investigation of the Cook County judicial system. "Every day you pick up a newspaper, some politician is going to jail or just getting out of jail," Quinn says. He also characterizes the state's property tax system as unfair and says that the state commitment to education has declined to where it is almost irrelevant in some districts.

Will Quinn be among those leading the charge? Probably. Quinn, who is now practicing law after being ousted from his job in Mayor Harold Washington's administration, says that unless he has a job that precludes him from political activity he plans to start beating the bushes after the first of the year. "It will be very educational for the people of Illinois, whatever way it goes."

Although Quinn sees plenty of need for changes, the Illinois State Chamber of Commerce sees none. President Lester W. Brann Ir. began a campaign against a new convention more than a year ahead of the vote. "The 1970 Constitution has served the state well with its specific safeguards for both corporate and individual taxpayers. By providing a stable tax climate, it has proven to be a solid economic growth document," Brann claimed. He also expressed fear that "anti-business and single-issue groups" would push for initiatives that would short circuit the legislative process.

But neither businessmen nor progressives matter. The elected officials do not control this question. No one does. It's up to the voters of Illinois to decide next year whether to call a convention that could rewrite the state's supreme law.