By Matt Bradley and Reem Abdellatif

    Egypt’s military gave Mohammed Morsi a 48-hour ultimatum to “resolve the crisis” before the military intervenes, setting the stage for a possible military coup a day after millions thronged Egypt’s streets demanding the president’s resignation on Sunday.

    So what’s next for Egypt, and what exactly is driving these protests? Here’s the rundown.

    Why are Egyptians protesting again?

    Egyptians are frustrated with the mounting economic pressures the country has faced over the past three years, and they are now also worried that President Mohammed Morsi and the powerful Muslim Brotherhood organization he once led are moving to install their people in all state institutions. Some protesters have expressed concern that Mr. Morsi’s Islamist supporters are aiming to “Islamize” an Egyptian culture known for its relatively moderate and Mediterranean outlook. They have accused the president of fulfilling only the goals of his party, which has recently appointed more Islamist governors and ministers.  The member of the hard-line Islamist Gamaa Islamiya movement he appointed as governor of Luxor—who resigned June 23 after days of protests—would have dealt a huge blow to its vital tourism industry, some protesters say.

    Agence France-Presse/Getty Images
    Protesters outside the presidential palace in Cairo Sunday

    Who’s who in this conflict? 

    A group of grass-roots young people known as “Tamarod,” or “Rebel” is a key player in this conflict. Many Tamarod members participated in the uprising against President Hosni Mubarak, and they are tapping into the declining popularity of Mr. Morsi and the Muslim Brotherhood. Egyptian artists, activists and poor Egyptians fed up with the economic crisis also turned out in droves at Sunday’s protests. Despite the protests against them, Mr. Morsi’s Muslim Brotherhood enjoys huge support from among Egypt’s moderate and conservative Muslims. Indeed, the organization’s candidates and positions have dominated every election since Mr. Mubarak’s fall.

    What do the protesters ultimately want?

    The protesters want Mr. Morsi to resign and call early elections, but they are divided on the details. Some want the military to step in, others have asked for a ruling council of politicians to take the helm while elections are prepared, while some want Maher el Baheiry, the head of the constitutional court, to take over temporarily in accordance with Egypt’s constitution.

    What will determine President Morsi’s fate?

    In 2011, it took 18 days of nationwide protests to spur President Mubarak to step down. But he had served for 30 years, was never elected and enjoyed far less public support. In the end, it was a military coup that hastened his exit. Now that the military has had a taste of power, it looks less likely to step up.

    Why are so many anti-Morsi protesters bashing the U.S.?

    Mr. Mubarak and his predecessor, Anwar Sadat, were both strong U.S. allies and both suppressed the Muslim Brotherhood for decades. But Mr. Morsi’s opponents have complained that since the revolution, the U.S. has treated the Brotherhood as if it is the sole entity on the political scene. Many in the opposition say the U.S. is treating Mr. Morsi the same way it treated Mr. Mubarak—as a client of U.S. interests.