Updated

After thousands of years as the land of the pharaohs and decades under dictators, Egypt could find its experiment with democracy brief, some analysts worry.

That concern follows the Muslim Brotherhood's wild success at the polls in post-Mubarak Egypt, most recently with the election to the presidency of Brotherhood candidate Mohammed Mursi. He was sworn in over the weekend.

Kori Schake, a research fellow at the Hoover Institution, feels Mursi and the Muslim Brotherhood's rise owes much to Egyptians' dislike of those candidates aligned with Hosni Mubarak and the Egyptian military. But the result is that the second-largest recipient of U.S. foreign aid is now led by a party with past ties to terror group Hamas.

"With the Islamist parties, because they are revolutionary, that is -- they seek to change the societies as they have been governed -- the fear is that you will get one man, one vote, one time," Schake said.

Schake went on to say the Brotherhood could adjust the peace treaty with Israel and has members who support Shariah law, which could mean fewer rights for women.

Former Secretary of State Condoleezza Rice questioned what those moves would mean for the tenuous U.S.-Egypt relationship.

"No American president can support an Egypt that calls into question the historic treaty between Israel and Egypt. And no American president can support an Egypt that doesn't fully recognize women's rights or the rights of religious minorities," Rice told Fox News.

Some experts think Egypt's military will ultimately pressure the government to keep the peace treaty with Israel and do so without trying to control the government.

"They particularly don't want to run things now because they know Egypt is headed for some real economic problems in the next year," Fox News security analyst KT McFarland said.

But the Brotherhood may be less predictable. It had promised not to run candidates for parliament or president, then ran candidates for both.

It is also the main opposition group in Jordan and Tunisia, and may well lead Syria should the regime of Bashar Assad fall.

And while some worry the Brotherhood will succeed in Egypt, Schake worries it will fail to bring security and prosperity, and that could bring a new fear: "That politics can't fix this, the routine ways we govern our societies can't fix this." This stalemate, she said, could lead to calls for violence.

She added: "I fear that that narrative may once again take hold as people get discouraged and despair." Schake calls that the Al Qaeda "narrative," and says Egypt would be its biggest prize.

Fox News' Wendell Goler contributed to this report.