What effect did that war have?

After the U.S.-led invasion of Iraq, sectarian tensions long kept in check by Saddam Hussein erupted into civil war between Sunnis and Shiites. Christians - Aramaic-speaking Assyrians with an ancient lineage - were caught in the cross fire. In the decade since the invasion, more than half of Iraq's Christians have fled to refugee camps in Syria or Jordan, reducing a prewar population of more than a million to some 400,000, mostly in the relatively tolerant enclave of Iraqi Kurdistan. In October 2010, just a few months after U.S. combat troops left, militants of al Qaida in Iraq laid bloody siege to Our Lady of Deliverance Church in Baghdad during Sunday evening mass, killing 58 people and wounding 78 more. "This tragic event sent a powerful message to Christians in Iraq - they are in grave danger and should leave the country," said Tiffany Barrans of the American Center for Law and Justice. Christians in Arab Spring countries would soon feel the same way.

Why did the Arab Spring alarm Christians?

Many Arab countries were ruled by secular dictatorships that ruthlessly repressed Islamic extremists and democrats alike. The revolts that began in Tunisia in late 2010 spread to Egypt, Libya, and then Syria. Many Christians declined to support the democratic uprisings, at least at first, because they feared that the fall of a dictator would mean the rise of an Islamist state. Once the dictators fell, Christians were branded anti-revolutionary and suffered a backlash. Islamists won large majorities in most of the post-revolutionary elections, and in some places, notably Egypt, they rewrote the constitution to give Islam a more central role in government and law.

How are Egypt's Christians treated?

Egypt is home to the Copts, the Middle East's largest Christian community, with some 8 million adherents. They consider themselves direct descendents of the ancient Egyptians, and still use the Coptic language, a derivative of ancient Egyptian, for religious services. Dictator Hosni Mubarak allied himself with the Coptic pope and protected the community in exchange for its support. Now Copts say the Muslim Brotherhood government of Mohammed Mursi is refusing to let them build churches and failing to crack down on a wave of violence against them. Islamic extremists bombed the Two Saints Coptic Church in Alexandria during the 2011 New Year's mass, killing 23 people and strewing body parts around the church. Later that year, a huge mob of some 3,000 Muslims burned the St. George Church in Edfu and torched nearby Christian homes. When Christians protested outside the Maspero state TV center in Cairo in October 2011, soldiers brutally attacked protesters, killing 27. "Maspero completely traumatized the Coptic community," said Heba Morayef, the director of Human Rights Watch in Egypt. "Feeling they were not protected by the law has created a climate of fear." Fear has also taken hold in the war zones of Mali (see below) and Syria.

What is happening in Syria?

Some of the world's oldest churches are in Syria, and until recently so were about 2.5 million Christians. For all its political repression, the country's Baathist dictatorship did at least guarantee freedom of worship, so when the uprising against President Bashar al-Assad began two years ago, most Christians sided with the regime or remained neutral. Now that Islamist extremists are joining the rebels in what has become a civil war, some 300,000 Syrian Christians have fled the country, and more will likely follow. "Everyone is afraid of these extremists," said George Nashawati, head of an Orthodox charity in Damascus. "Look what happened in Iraq. It could happen here."

How has the U.S. responded?

It has strongly condemned attacks on Christians, but it has not gone beyond rhetoric. The U.S. Commission on International Religious Freedom, a bipartisan federal government body, has recommended that the State Department list Egypt and Iraq as severe religious freedom violators, like Iran, which aggressively persecutes Christians, or Saudi Arabia, which bans all non-Islamic religions. But the White House has so far refused. U.S. Rep. Frank Wolf (R-Va.), who recently traveled to Egypt, said Copts believe that the U.S. has made a bargain with the Muslim Brotherhood. "The feeling is that as long as the Brotherhood protects the United States' interests in the region, it can act with impunity within its borders," Wolf said.

Christians flee Mali

Mali had no Arab Spring uprising, but it has seen a fierce Islamist insurgency. In 2012 Salafist extremists linked to al Qaida took over in the north, where they destroyed churches along with Muslim shrines. Islamist rebels singled out the small Christian minority for torture and summary executions, and as many as 200,000 Christians from Mali fled to refugee camps in Algeria and Mauritania. "I deplore the departure of the Christian community," said Timbuktu Mayor Ousmane Halle, a moderate Muslim, shortly after the Islamists invaded his town. "But I cannot guarantee their safety. And these are people that have lived side by side with us for centuries."