On Nov. 12 one protester, a supporter of Druze politician Walid Jumblatt, was shot dead in an altercation with soldiers. The soldier who fired on him has been detained.
Several leading politicians have warned that the protests are comparable to previous times of serious tension.
Lebanon's caretaker defense minister Elias Bou Saab said the situation is "very dangerous," Reuters reports. The unrest reminded him of the start of the country's devastating civil war, which lasted from 1975-1990.
In their letter, Anderson and Broglio cited the words of Pope John Paul II: Lebanon "is more than a country, it is a message of freedom and example of pluralism for East and West."
"We pray that peace and security may come to this region, and that those who have suffered so much may be able to rebuild their lives in an environment consistent with their rights to human dignity," they added.
"We continue also to watch closely and with concern the situation in other countries in the region where so many have suffered from war and violence, and in the case of Christians, have been targeted often simply for professing their belief in Christ."
The U.S. invasion of Iraq in 2003 destabilized the region and led to many Iraqis - Muslim, Christian and others - fleeing their country. A March 2011 revolt against Syrian President Bashar Assad quickly drew support from the U.S. and regional powers, with Russia and others siding with Assad against the rebels. The resulting civil war, which is ongoing, has killed an estimated 400,000 people and forced millions to become internally displaced persons or refugees who fled abroad.
As of Oct. 31 there were about 1 million U.N.-registered Syrian refugees in Lebanon alone, a country of fewer than 6.9 million residents. Its political and social systems are a sometimes delicate, always complex balance of rival factions splitting the loyalties of Christians and both Sunni and Shia Muslims.
In 2014, the Knights of Columbus launched an advocacy campaign for Christians and other religious minorities in the Middle East. The organization has given about $25 million to support persecuted religious minorities from Iraq, Syria and elsewhere in the region.
The fraternal organization launched a successful effort to secure the U.S. State Department's recognition of the Islamic State group's crimes against Christians, Yazidis and others in Iraq and Syria as genocide. In 2016 the U.S. Congress unanimously passed a resolution declaring that the Islamic State group had committed genocide. Then-Secretary of State John Kerry recognized the group's actions as genocide as well.
Advocates of the official designation said it could aid investigation and indictment of those responsible for genocide and would emphasize the obligations of the U.S. government under international conventions against genocide.
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In a separate Nov. 15 opinion essay at the New York Post, Anderson said that a mass exodus of Christians from the Middle East would be catastrophic.
"What happens in the next few weeks in Iraq, Syria and Lebanon is crucial for Mideast Christians - and the stability and pluralism of these countries and the wider region," he said.
While Christians made up about 20% of the population a century ago, they are now 5% or less, he said.
"In Iraq, protesters are demanding an end to sectarian government and equal citizenship for all regardless of ethnicity or religion," he said, blaming protester deaths on "Iran-backed militias."
"The future of the Iraqi state hangs in the balance," he continued. "Either it will become more sectarian under the influence of its more powerful neighbors - or it will become the pluralistic country sought by thousands marching in the streets, including Christians."
In Lebanon, Anderson said, Christians fear an economic collapse that could result in the fall of the largely Christian Lebanese Army, resulting in crisis and mass emigration.