CAIRO – The downtown section of the capital will be in lockdown today as the country prepares for the trial of two judges who have challenged the legitimacy of last fall’s parliamentary elections.

The trial of Hisham Bastawisi and Mahmoud Mekki was cast into doubt when it was confirmed that Mr. Bastawisi had suffered a heart attack and was rushed to Cleopatra Hospital for emergency open-heart surgery.

Meanwhile, the Interior Ministry issued a warning that no one without explicit permission from the Supreme Judicial Council would be allowed in the vicinity of the supreme courthouse, the site of the trial.

The combination of the politically charged trial, which has already sparked a rebellion of some 2,000 judges, and the heavy security force being prepared for downtown signal the end of nearly two years of political liberalization in Egypt.

In 2004, President Mubarak allowed an opposition group known as Kafiya (Arabic for “enough”) to stage open protests calling for his downfall. While the demonstrations often attracted only a handful of dissenters, the regime’s reaction to the judges’ recent civil disobedience has led to what appears to be a reversal of a policy of political tolerance.

Last week, 16 demonstrators were arrested for protesting the judges’ prosecution, and members of the judiciary claim to have a video of one of their number being beaten and pulled into a police car.

Meanwhile, an air of mystery surrounded Mr. Bastawisi’s sudden ill health. A spokesman for the Cleopatra Hospital said yesterday that the judge “came to the hospital suffering from severe chest pains that came from a clot in the front wall of the heart.” The spokesman added that the judge was in stable condition after surgery.

Reuters yesterday quoted the president of the judges’ syndicate – which is organizing the protest in solidarity with Mr. Bastawisi – as saying he was in no condition to attend the trial. “They gave him seven electric shocks,” Zakaria Abdel Aziz told Reuters. “Of course he cannot go on trial tomorrow.” Mr. Abdel Aziz added that Mr. Mekki would not attend the trial without Mr. Bastawisi.

A story in the independent magazine Egypt Today quoted an Interior Ministry official as saying there was a ban on all demonstrations in front of the courthouse today because of the adverse effects large numbers of protesters have on the city’s already clogged traffic.

Signs of a crackdown on dissent have been evident in the city all week. The building that houses the judges’ syndicate is all but surrounded with military vehicles and uniformed riot police. A guard from the riot police has been placed at the entrance to the syndicate, the base of operations for the judicial rebellion.

Opposition groups reported clashes on Tuesday between protesters and the police over the judges’ standoff with the Mubarak regime in the town of Shibin el-Kom.

The stakes are high for Mr. Mubarak. The vice president of the judges’ syndicate, Mohammed Nagy Derbala, said in an interview this week that the judges are considering escalating their protest and will refuse to hear cases if Messrs. Bastawisi and Mekki are stripped of their positions.

Mr. Bastawisi said on Monday that he would not attend his own trial and implied that Mr. Mekki would not if the two men were not allowed to choose their own counsel and submit evidence.

The timing for Mr. Mubarak could not be worse. This weekend, he is hosting a regional meeting of the World Economic Forum, to be attended by Israel’s foreign minister, Tzipi Livni, Senator Hatch, a Republican of Utah, and the chairman, chief executive officer, and president of Citibank, William Rhodes, in the seaside resort of Sharm el Sheikh.