On January 11, I warned about the coming turmoil in Egypt in the pages of the Investor’s Business Daily, writing that “Egypt [was] on the brink of what could be a chaotic transition in power, [with] those who would lead that nation bear[ing] closer scrutiny.”

For the first couple of days of unrest in Egypt, the Muslim Brotherhood, Egypt’s largest, best-organized and most potentially ruthless opposition group, sat on the sidelines.

As expected, after Friday prayers at mosques around the country, the "Ikwan," as the Muslim Brotherhood is known, swung into action, swelling the protests and escalating the violence.

Now the key question for the Arab world’s most important nation is who will lead Egypt? In spite of popular, mass protests, and the pleasant, familiar to Westerners face of former U.N. nuclear inspector Mohamed ElBaradei, now under house arrest, there are really only three groups with the power to end up leading Egypt: the Mubarak family, the military and the Islamists in the form of the Muslim Brotherhood.

President Mubarak, 82, has been in power since 1981-- when a hail of Islamist gunfire felled Anwar Sadat. He had been grooming his son, Gamal Mubarak, 48, an investment banker by profession, to run for president in elections scheduled for late this year. That plan has died in the chaos of Cairo’s streets.

Lieutenant General Omar Suleiman, 74, Egypt’s spy chief since 1993, is the leading military rival to Gamal. That the military’s discipline appears spotty in this crisis bodes ill for both General Suleiman and Mubarak.

That leaves the Muslim Brotherhood, a well-organized but outlawed group with mass support among Egypt’s poor and religiously inclined people. The Ikwan is in a roughly analogous position to the Communists in Russia in 1917, whose iron will and willingness to use violence required only seven months to seize power from the fragile transitional government that overthrew the czar.

Just who is Egypt’s Muslim Brotherhood? Are they violent and anti-Western, or can we work with them?

Egypt’s Muslim Brotherhood takes its religious and ideological cues from Sheikh Youssef Qaradawi, one of the most important Sunni Islam voices in the world. Qaradawi, an Egyptian, lives in exile in Qatar.

Qaradawi is an Islamist who knows how to look like a moderate to Western observers – but his core beliefs are anything but moderate. Should he return from exile to Egypt, look for Egypt’s Muslim Brotherhood to ascend to power in a manner reminiscent of the mullahs in Iran under the Ayatollah Khomeini in 1979. And, should the Ikwan prevail, Egypt’s sizable Coptic Christian minority and Egypt’s historic peace with Israel will both be at risk.

Chuck DeVore served in the California legislature from 2004 to 2010. He is a lieutenant colonel in the U.S. Army (retired) Reserve and served as a Special Assistant for Foreign Affairs in the Reagan-era Pentagon. He studied abroad at the American University in Cairo in 1984-85.