It is true that Muslims are today a demographic majority in every country of the Middle East except Israel. (Even there, however, Muslims would be nearly a majority, if Palestinians in the Palestinian Territories had the same citizenship rights as the Israeli settlers.) But such a blanket statement obscures more than it reveals. There is a vast difference between Iran, which is almost 100% Muslim, and Lebanon, where Muslims are less than two thirds of the population and the government is divided roughly evenly between Muslims and Christians (with the requirement that the president be a Maronite Christian and the Prime Minister a Sunni Muslim, among various other requirements). Granted, the population of Iran is many times that of Lebanon, but the point is that the other countries in the region (including Egypt, Turkey, and Iraq, all very populous) are between these two extremes.
Nor are all Muslims alike. Differences between Sunni Muslims and Shiʿites are only the tip of the iceberg: at least four “legal schools” of Sunnis and several branches of Shiʿa Islam all have different requirements and regulations. Fellow feeling between Sunnis and Shiʿites is a very recent development, and has not overcome sectarian violence in Syria and Iraq nor the regional rivalry between (Sunni) Saudi Arabia and (Shiʿite) Iran. These differences are independent of the gradations between secularist and devout Muslims or between modernist and Salafi Islam. Intra-Muslim diversity means that Muslims may feel more fellow feeling with certain non-Muslims than with other Muslims, and the demographic strength of Islam is more attenuated. This also leads to greater differences between countries: Egypt has more Coptic Christians than Shiʿites, while Iraq is about two-thirds Shiʿites and one third Sunnis.
When the historical perspective is taken, the present overwhelming demographic dominance of Islam is seen as a relatively recent development in some parts of the Middle East. The Middle East has been mostly ruled by Muslims since the seventh century, although the Byzantine Empire continued to rule most of what is today Turkey until the eleventh century, the Crusaders ruled parts of eastern Turkey, western Syria, Lebanon, and Palestine/Israel for a couple centuries, and most broadly but most briefly the non-Muslim Mongols under Hulegu and his successors conquered all of Iran, Iraq, most of Turkey, and (repeatedly but ephemerally) Syria. The religion of the rulers is frequently taken as characteristic of the religion of the land, and so the Middle East is often called the “land of Islam,” in Arabic dar al-Islam, or the “central Islamic lands.” That this term doesn’t simply mean that Islam came from the Middle East is shown by the fact that the Middle East is never called, by parallel, the “land of Judaism” or the “land of Christianity,” though both also came from that region. In French, the confusion between religion of the ruler and religion of the land is even starker: areas under Islamic ruler are simply labeled l’Islam.
But the religion of Muslim rulers should not be taken as determinative for the population as a whole. Muslim rulers frequently employed non-Muslims to carry out bureaucratic work, at least into the fifteenth century in much of the Middle East, and later in Ottoman Constantinople. With rising European interest in the Middle East, local Christians and Jews were often the translators and intermediaries between the newly arrived foreigners and the local Muslim rulers and populace. Middle Eastern non-Muslims did not only attain prominence through European intervention, however: Faris al-Khoury was already in government before the French claimed Syria in 1920, and went on to become Prime Minister of Syria twice, though a (Greek Orthodox turned Presbyterian) Christian. Tariq ʿAziz was the deputy Prime Minister of Iraq under Saddam Hussein, and a Chaldean Catholic (a group of native Iraqi Christians who, beginning in the 16th C, started entering communion with the Roman papacy). George Sabra, an active voice in the Syrian Civil War, has been president of the Syrian National Council and acting president of the Syrian National Coalition (the opposition group favored by the USA and Western Europe). The history of the Middle East, even in the last century, cannot be told accurately without naming certain key non-Muslims.
Although these individuals are exceptional, they are not unique. They are rare because they are at the highest echelons of government, where they were not selected because of but despite their non-Muslim religious affiliation. Many more non-Muslims have been employed by Middle Eastern governments, both pre-modern and modern, at lower ranks. And the broader population of non-Muslims, not employed by government, was a significant portion of many Middle Eastern countries into the twentieth century. Before 1915 in eastern Anatolia and 1923 in western Anatolia, Christians were almost a fifth of the population (mostly Armenians and Syriac Christians in the east, Greeks in the west) in what would become the Republic of Turkey. Such a proportion means that, depending on levels of integration, every Muslim would know not merely one but several Christians, and may need to do business with them. Christianity in Iraq has dipped from 10% around the middle of the 20th C to less than 2% today. We do not know when Muslims became even a bare majority of the population in Egypt or Syria, but it was certainly not before 1250. That may seem like ancient history to many modern readers, but that means Islam spent at least six centuries as a ruling minority religion, almost half of the history of the “Islamic” Middle East to date, and both countries still have Christian minorities around 10% of the population, absent from parts of the countryside but certainly visible in all cities.
Today a higher proportion of Middle Easterners are Muslim than at any point in the past, but the proportion has changed significantly even within the last century. Nevertheless, Christians have continued to play a prominent, if subordinate, role in government. And the divisions between different Christian and Muslim groups reduce the sense, within the Middle East, that “basically everyone agrees with me.” People from the Middle East know there is religious diversity. For westerners to regard the Middle East as “Islam + Israel” is negligently over-simplistic.