JUDY WOODRUFF: Finally tonight, we come back to the unrest in the Muslim and Arab world.
Pope Benedict wrapped up a three-day visit to Lebanon today, a long-planned trip that was overshadowed by the anti-American protests in the Middle East. But the flare-up in violence was just the latest in a series of events and conflicts that have many Christians in the Middle East uncertain about their future.
Ray Suarez has the story.
RAY SUAREZ: Thousands turned out throughout Lebanon to get a glimpse of the leader of the Roman Catholic Church. But, while many were focused on the pageantry of the visit, the region's problems weren't far away.
In Tripoli, Lebanon, one person was killed Friday over protests of an anti-Islamic film. Last month, at least 16 people were killed in sectarian strife in the city, more than 100 injured.
Over the border in Syria, civil war rages on. According to activists, more than 24,000 people have been killed in the conflict. Nearly a quarter million have become refugees.
As strict interpretations of Islam have become more widespread across the Middle East, Christians have continued to leave.
While speaking in Beirut Sunday, the pontiff made a special call for peace and coexistence while speaking to thousands at an open-air mass.
POPE BENEDICT XVI, Roman Catholic Church (through translator): You are very well aware of the tragedy of conflict and violence that leads to so much suffering. Unfortunately, the sound of arms can still be heard, in addition to the cry of widows and orphans.
Violence and hatred are sweeping over life and women, and children are the first victims. Why so much horror? Why so many dead?
I call on the international community, I call on Arab countries to propose all possible solutions that respect the dignity, rights and religion of each person.
RAY SUAREZ: Once the pope was gone, it was back to business as usual. The militant group Hezbollah, which had recently supported the pontiff's trip, called for a week of protests over the controversial film which has much of the Muslim world up in arms. Hezbollah leader Sheik Hassan Nasrallah personally led protests today.
This Christian boutique owner told the NewsHour that events like these weigh heavily on the minds of those in her community.
ZALA MOUZNARE, Lebanese Christian (through translator): The life of Christians in Lebanon, I find that they're always afraid with everything that is happening with the Islamists.
RAY SUAREZ: Mary-Jane Deeb, head of the Africa and Middle East division of the Library of Congress and an Egyptian-born Christian, says the long-term pressures on Middle Eastern Christians have steadily gotten worse.
MARY-JANE DEEB, Library of Congress: They are under pressure. There have been wars. There have been civil strife.
There have been economic and political developments that have undermined their status in the region. And, certainly, today, they are dwindling.
RAY SUAREZ: The causes are many, the war in Iraq, the tumult unleashed in the Arab spring, even the education and foreign contacts that have made it easier for Arab Christians to emigrate. In Iraq, Syria and Egypt, longtime protectors, Arab strongmen can't protect Christians as they once could.
MARY-JANE DEEB: The Christian communities didn't constitute a threat to existing regimes. So they were put, in a way, under the wings of some of those governments, because they saw them as an educated -- educated minorities.
But, of course, in the case of Egypt, it was a two-sided sword, if you want. When it served the interests of the government, yes, Egypt's government would protect the Christians.
But when the government needed to appeal to more radical Muslim feelings, then it allowed Coptic buildings, areas to be ransacked or attacked by radical Islamists.
RAY SUAREZ: The numbers certainly are not positive. Christians today make up about 5 percent of the entire Middle Eastern population. That's down from about 20 percent a century ago.
According to some estimates, the total population of Christians in the Middle East, roughly 12 million, could be cut in half over the next eight years.
In Egypt, the country with the largest number of Christians in the Middle East, an estimated 93,000 Copts left in 2011 alone, as Egyptian President Hosni Mubarak fell from power and members of their community were attacked. Some Copts don't have much hope for the future.
SALLY SAMIR, Egyptian Coptic (through translator): We are much oppressed. We have lost our sons, and they were not guilty. Why were they killed? Why have the mothers been bereaved?
RAY SUAREZ: Others, like this Christian cleric Fayez Nayyef, believe coexistence is possible.
FAYEZ NAYYEF, Egyptian cleric (through translator): The way that people are thinking should be changed.
I want to tell everybody that the main target is not only causing rifts between Muslims and Christians, but also it seeks to entice our unity. Those people with hard-line thoughts should think big about the future and change.
RAY SUAREZ: In Israel, the numbers of Christians are actually rising, while in Gaza and the West Bank, home to the birthplace of Jesus, numbers are trending downward, as the area copes with extremism and financial hardships and limited physical movement.
In Iraq, after the fall of Saddam Hussein, an estimated two-thirds of 1.5 million Christians fled their homes and churches. Priests have been murdered, churches attacked, some Christians moved to safety in northern Iraq. Others left the country.
In Syria, President Bashar al-Assad has long had the reputation of protecting the ancient Christian communities. As restless Muslims radicalize, Christians felt exposed.
MAN: Only the secular government can preserve the existence of Christians in the Middle East.
And, after all, during the government of Assad or the other government, we lived in Syria with freedom, religious freedom. We have our freedom to worship and to build the churches.
RAY SUAREZ: Mary-Jane Deeb says Syrian Christians are exceptionally vulnerable.
MARY-JANE DEEB: The Christians are caught between a rock and a hard place, because, on the one hand, there's the government that was at least protecting them to some extent that is under siege.
On the other hand, the Syrian Christians are afraid of who will take power afterwards. If it is a radical Islamist group, it will undermine their positions, their privileges and even their security. It is difficult for them then to support that opposition.
RAY SUAREZ: Christians in Lebanon fare better in many ways than their counterparts in other countries. The country's head of state by law must be a Christian. And Muslims and Christians have hundreds of years of relatively peaceful coexistence.
The outcome in Syria's civil war, for the country, for Assad, for Syria's Christians, is still unknown.
Can you imagine a day where some of the great historic places of Christianity will simply have few or no Christians?
MARY-JANE DEEB: There are no more Christians in Algeria, in Tunisia, in Libya, where there was a majority of Christians 700, 800 years ago. They're gone. There's not -- there's no one.
So it is not difficult to imagine that, in the rest of the region that will also happen as more Christians are emigrating. They're leaving. They're going to Australia. They're going to the States. They're going to Europe.
RAY SUAREZ: Meaning the current instability carries the risk of not just further shrinking Christianity in the religion's birthplace, but bringing its disappearance that much closer.
JUDY WOODRUFF: You can see a slide show of images from the pope's visit to Lebanon on our website. Find that on the Rundown.