CAIRO -- An Islamist-backed constitution appeared headed for approval on Saturday, propelling Egypt's deeply divided political factions into a new phase in the battle over the country's future.
As millions went to the polls for the final round of a referendum, all sides predicted that the charter would win approval, marking an important milestone in Egypt's chaotic two-year transition to democracy.
But the hastily drafted document leaves unresolved many questions about the character of that democracy, including the Islamists' commitment to individual freedoms and their opposition's willingness to accept the results of the political process without recourse to violent street protests.
The charter's path to the referendum has also pushed Egypt to the brink of civil strife, exposing the alienation of the Christian minority, the political opposition's refusal to negotiate and the Muslim Brotherhood's willingness to rely on authoritarian tactics.
How those tensions are managed and the new constitution is put into effect will determine whether Egypt returns to stability or plunges further into discord, and much of the region is watching the outcome of that definitive Arab Spring revolt.
Neither supporters nor opponents of the charter said they expected an immediate end to the partisan feuding that has torn at the country in the month before the vote. The Islamists allied with President Mohamed Morsi said they intended to rebuild trust by using the new charter as a tool to battle remnants of former President Hosni Mubarak's government. Old laws and prosecutors, the Islamists say, are protecting loyalists and holdovers while they obstruct change from within the bureaucracy and conspire with the opposition to stir up unrest. Leaders of the anti-Islamist opposition, however, said they hoped to carry the momentum of their struggle against the constitution into the parliamentary elections set to be held two months from now. They accused the Islamists of using the specter of a struggle against remnants of Mr. Mubarak's government as a pretext to demonize the opposition and take over the machinery of the state.
"If we accept the legitimacy of working within the system, they have to agree that the opposition is legitimate," said Amr Moussa, a former foreign minister under Mr. Mubarak and a presidential candidate who has re-emerged as an opposition leader during the constitutional debate. "The ancien régime is finished. They are imagining things. They are imagining that if you say no to the constitution, as I have done, then you are part of a conspiracy to topple them."
Both sides of the ideological divide appeared to dig in.
"A crack has emerged in Egypt; there's a gap, there's blood and deaths, there's extremism," said Ahmed Maher, who helped jump-start the revolution as a leader of the secular April 6 Youth Group and then served as a delegate in the constituent assembly that wrote a draft of the charter. "Something has happened between Egyptians that would make the results bad no matter what the outcome" of the constitutional vote, he said, predicting further clashes before the parliamentary elections.
Adding to the uncertainty about what may come next, Mr. Morsi's vice president, Mahmoud Mekki, resigned Saturday. The draft constitution would eliminate his position, And Mr. Mekki, a former judge, said that he had originally submitted his resignation in early November before a series of crises postponed it.
"The nature of political work does not suit my nature as a judge," he said.
The turnout for Saturday's voting appeared to be low, as it was last week. At one polling place in the dense Mohandiseen district near Cairo, the station was empty in the middle of the day. The low turnout may have reflected a lack of enthusiasm or perhaps a consensus among Egyptians that after last week, the charter's approval was a foregone conclusion.
Mr. Morsi's advisers said that after the ballots were counted in coming days he would deliver a televised address calling for unity and reconciliation. His critics said that to be credible he would need to strike a tone different from that of his previous address. In it, he had blamed a conspiracy of foreign agents, Mubarak cronies and his political opponents for a deadly night of street fighting between his supporters and other protesters.
In what Mr. Morsi's advisers called a significant step toward reducing tensions, the president plans to appoint some of his opponents to the Islamist-dominated upper house of Parliament. Although largely powerless, it will act as the main legislature until the coming re-election of the lower house, which was dissolved by the courts.
Advisers to Mr. Morsi, who has the power to name 90 of the 270 seats, said he was expected to announce a roster of upper house appointees that would include eight representatives selected by the leaders of Egypt's Coptic Orthodox, Catholic and Protestant churches. That was more than the number of representatives chosen by Egypt's highest Muslim authority, Al Azhar. At least four other appointees are Christian as well, his advisers said.
Most members of Egypt's Christian minority, about 10 percent of the population, have opposed the new constitution since the Coptic Church withdrew its representatives from the constitutional assembly in a dispute over the role of Islamic law in Egyptian jurisprudence.
Presidential advisers said the 90 presidential appointees would include members of 15 political parties other than the Muslim Brotherhood's Freedom and Justice Party and the ultraconservative Salafi party Al Nour.
The leaders of the main opposition coalition have refused to negotiate with Mr. Morsi or take seats in the upper house. His Islamist allies will still dominate, they say. Islamists won more than 70 percent of the seats in the parliamentary elections in late 2011. But their opponents see an opportunity to gain seats in the coming Parliament because of the backlash against Mr. Morsi's heavy-handed attempts to force the constitution to a vote. Mr. Morsi pushed ahead over the objections of his opponents, judges and the Coptic Church.
Mr. Moussa and others have said they hope the coalition forged to fight the constitution can hold together as a bloc in the elections. But if the anti-Islamist bloc does hold together, some worry it will force the mainstream Islamists of the Muslim Brotherhood into closer collaboration with the ultraconservative Salafis, reinforcing sectarianism and polarization.
Moataz Abdel-Fattah, a political scientist and former delegate in the constitutional assembly, said neither side appeared willing to respect the views of the other.
"We have an elite running its affairs according to a strategy of stubbornness," he said. "Everybody is trying to understand what the other side wants so that they can ask for the exact opposite."
This article originally appeared in The New York Times.