On April 13, 1975, Lebanon was plunged into a civil war that destroyed the "Switzerland of the Middle East" forever.  I lost my only brother and sibling in that war.

And since 25% of Arab Americans are Lebanese, I write this article in memory of the victims of that war.  We can also derive important lessons for America today from the civil strife that devastated my native country.

Battle damage in Beirut from the long civil war was extensive (YouTube screen grab).

First, a bit of history.

In 1920, after World War I, Greater Lebanon was declared a state and placed under the French Mandate in 1923.

Because the state had a Christian majority, the French mandated a Christian president and commander in chief, unlike any other country in the region.

In 1943, after independence from France, the major confessional communities (Christian, Sunni, Shiite) forged an unwritten National Pact.  The president would always be a Maronite Christian, the prime minister a Sunni Muslim, and the house speaker a Shiite Muslim.

Lebanon enjoyed decades of prosperity under a free-market economy and was known to be the most democratic country in the Middle East, second only to Israel.

However, in a few decades, because of a higher birth rate, Lebanese Muslims outnumbered their Christian compatriots.  Muslims wanted more political representation and power and called upon the Lebanese government to join the pan-Arab nationalist movement and distance the Lebanese state from Western influence — mainly from the Baghdad Pact.

The Lebanese divide over Arab Nationalism and the Palestinian Question hardened into longstanding disagreements among the confessional communities.  The breaking point came with the Cairo Agreement in 1969.  Brokered by the late Egyptian president Jamal Abdul Nasser, it gave the Palestine Liberation Organization (PLO), led by the late Yasser Arafat, control over the sixteen Palestine refugee camps in Lebanon.  Control passed from the Lebanese Armed Forces to the Palestinian armed command.

The PLO developed a state within a state, obtaining funds and arms from both the Arab states and Eastern Europe, disregarding Lebanese law.

Lebanese Christian elites were alarmed by Palestinian military actions and were losing their grip on the country.  Right-wing Christian parties armed their rank and file, preparing for a showdown.

The PLO launched propaganda campaigns, dubbing the Christian elites as reactionary "Isolationists" and collaborators with Israel. Arafat declared, "The road to Jerusalem goes through Jounieh (a Christian stronghold north of Beirut)."

This brings us back to April 13, 1975.  Phalangist militia attacked a bus carrying Palestinians and Muslims, killing 27 and injuring others.  The attack was in retaliation for a failed assassination attempt the previous day on their leader, Pierre Gemayel.

The tit-for-tat launched a civil war that raged for years.  More than 150,000 Lebanese and Palestinians were killed, and more than 20,000 people were kidnapped and disappeared.

Both Palestinian and right-wing Christian militias perpetrated massacres.

In 1982, Israel invaded Lebanon in order to stop Palestinian attacks on north Israel, put Beirut under siege, and was locked in battle with the Palestinian militias and their Lebanese allies who took their last stand there.  However, Washington was able to broker a ceasefire that resulted in the evacuation of the PLO from Beirut.

The Multi-International Force, led by the U.S., came to Beirut to support peace and the country's reconstruction.  But the collaboration of Iranian, Syrian, and Lebanese Shiite extremists foiled Western plans for Lebanon.  After the October 1983 barracks bombing that killed 241 U.S. and 58 French servicemen, Ronald Reagan, then U.S. president, withdrew all U.S. troops.  Lebanon again plunged into violence.

Today, Hezb'allah, the Iranian-Lebanese Shiite terrorist militia, controls Lebanon, which also suffers from U.S. economic sanctions on Iran.  What was once the Switzerland of the Middle East is now a satellite of Iran and Syria.

What can Americans learn from Lebanon's debacle?

First, as Raymond Ibrahim, an expert on political Islam, explains in what he calls "The Islamic Rule of Numbers," when Muslims reach a large minority, they ignore civil rights, become more belligerent, and seek to impose aspects of their honor-shame culture on others.  This is happening in places like Dearborn, Michigan, where American Lebanese Shiites support Hezb'allah.

Second, Palestinian political activists, wherever they live, suffer from what I would call an "Israeli-Jewish" complex.  This complex drives them to place the annihilation of Israel, as a goal, above their community's interests and the interests of their host countries.

It has happened in Jordan and Lebanon and is now happening in the southern suburbs of Chicago, where Palestinians have become almost 20% of the population.

Over the last three decades, Palestinian organizations have mushroomed, turning the southern suburbs of Chicago into a hotbed of radical anti-Semitism and an anti-Western conclave.  Many American Palestinians there support Hamas and Islamic Jihad.

Third, when Muslims are a minority, they engage in a "cultural war." Ibrahim explains, where "Muslims are less than 1% of the population (…)  Islamic assertiveness is limited to political activism dedicated to portraying Islam as a 'religion of peace,' and sporadic, but clandestine, acts of terror."

How can we preserve the freedoms in America when we understand those tactics?

Extreme vetting for Middle Eastern immigrants is necessary. U.S. Homeland Security is lenient with Jordanian would-be immigrants, although more than 90% of them are of Palestinian descent, and many support the Islamic State (ISIS) and terrorism against Israel. Likewise, many Lebanese immigrants support Hezb'allah, and should be thoroughly vetted.

American authorities should take the issue of integration seriously. Many American Muslims are not assimilating. Authorities should push against child marriages and for education among young Muslims.

Law enforcement agencies should keep close watch over Palestinian and Islamist organizations. Do not give them a pass, as the Lebanese authorities did.

I appeal to my fellow American Lebanese and American Palestinians to appreciate and guard the freedoms we enjoy in this great country. Our new home offers rights and privileges that we did not have in our countries of origin. I call upon us to defend this great nation against all dangers.

Muhammad, the Prophet of Islam, wisely compared the community to a boat. All are responsible for the maintenance and security of the boat. If those passengers staying at the lower level drill a hole, all the boat [community] will sink.

Hesham Shehab is an Illinois Middle East Forum associate.