Secretary of State Hillary Rodham Clinton cautioned Sunday that Egyptians have to overcome numerous obstacles to pull off elections in September to replace President Hosni Mubarak and acknowledged that ousting him beforehand might roil the transition to democracy.

Clinton made her comments as the administration appeared to be realizing the risks and complexities of a transition to democracy in a key strategic ally of 80 million people.

Administration officials have distanced themselves from remarks Saturday by Frank Wisner, a presidential envoy to Egypt, that Mubarak should guide the transition rather than stepping down.

On Sunday, Clinton said repeatedly that it was up to Egyptians, not Americans, to decide Mubarak’s role.

But she noted that under the Egyptian constitution, if Mubarak resigned he would be replaced by the speaker of the House, and elections would be required within 60 days.

“The Egyptians are the ones having to grapple with the reality of what they must do,” she told reporters. She added that some Egyptian opposition leaders have said that 60 days is not enough time to organize political parties and an election. “That’s not us saying it,” she said. “It’s them saying it.”

Mubarak’s resignation is the central demand of hundreds of thousands of protesters who have jammed downtown Cairo and held noisy demonstrations in other Egyptian cities for nearly two weeks.

Wisner said Saturday that if Mubarak stepped down and snap elections were held, the opposition could be forced to compete under existing electoral laws favoring the ruling party, which it probably would refuse to do.

The next regularly scheduled Egyptian presidential election is in September, and Mubarak has pledged not to run, in a major concession to protesters.

Clinton stressed that the U.S. government was trying to avoid publicly taking sides in Egypt’s tumultuous internal politics. She declined to express an opinion on the decision by the Muslim Brotherhood to hold talks Sunday with Egyptian Vice President Omar Suleiman, the government’s lead negotiator.

“I am not going to be prejudging who is going to participate in this political process,” she said.

The U.S. government has been wary of the Brotherhood, Egypt’s largest opposition group, because of its support for Islamist groups such as the Palestinian Hamas movement, which is on the U.S. terror list.

Clinton laid out in greater detail than before the steps that Egyptians must take for a peaceful transition, urging them to set benchmarks and deadlines on reforming the constitution, changing undemocratic laws and preparing for elections.

She said the United States and other countries were ready to offer technical experts to help.

“You don’t want to get to September and have a failed election and have people say, ‘Wait a minute. What was the point of this?’” she said. “You want to help set the stage for the kind of credible, legitimate elections that are going to produce winners that people will believe — whether they voted for them or not — represent Egypt.”