This sense of immunity and dismissal led to the downfall of many countries throughout time.

What does being the second-largest religion in a country mean? Voters impact local and national politics, swing domestic elections, elect more representatives from the same religious affiliation, are influential enough to determine who the next president of the United States may be, and change the laws of the land.

Many extremist Muslims believe that their religious desire is coming true in in the US. Religiously speaking, for extremist Muslims, ruling America is Allah's (God's) word. To them, a sacred promise is coming to fruition.

"Soon," said the letter, "America Will Be Ours".

"Ours?"

The writer, it became clear, was an extremist Muslim in the U.S. who claimed to be a reputable religious preacher. With each new word, concern grew.

He pointed out, throughout the letter, the "sinful" ways of the West: dancing, drinking, dating...

He expressed disgust that most women did not wear the hijab or participate in prayer five times a day. Then he got straight to the point: "Ours," he explained, represented Muslims like him.

The sentiment is hardly a new one. A person hears similar proclamations from many Muslim extremists throughout the years. The real shock was not letter but the reaction of many Americans after seeing it.

Such a thing, they said, could never happen. The writer's words were "just bluster," nothing to be taken seriously. Most surprisingly, they stated -- honestly -- that Muslims who speak of such intentions do not really mean what they say, so these threats should not be cause for concern.

The history of the two nations where I grew up -- Iran and Syria -- taught all of us there a big lesson about living in this kind of ignorance: the reality of how quickly a nation can be consumed by the philosophies of a religious state. An authoritarian and malicious regime, as exists now in Iran -- the world's leading sponsor of terrorism and brutal even to its own people -- is something we cannot forget.

In a few centuries, in Syria, where more than 90% percent of the population were Christians, and in Iran where an overwhelming majority of citizens were Zoroastrians, the demography drastically shifted to majority-Muslim. Neither nation could have anticipated such a change.

While many may underestimate the radical preacher's claims that "Soon, America Will Be Ours", for extremist Muslims these beliefs are strongly and deeply rooted.

Many extremists believe that their religious desire -- for a "Muslim takeover of the White House, a directive from Muhammad himself " -- is coming true in the US. Religiously speaking, for these Muslims, ruling America is Allah's (God's) word, a sacred promise is coming to fruition.

A recent survey and demographic research released by the Pew Research Center found that Muslims will soon overtake members of other religions, including Jews, as the second-largest religious group in the United States.

This issue should not be taken lightly. What does being the second-largest religion in a country mean? Voters impact local and national politics, swing domestic elections, elect more representatives from the same religious affiliation, are influential enough to determine who the next president of the United States may be, and change the laws of the land. All it takes is a subtle shift in power for the entire society, political system and culture of a nation to be changed.

The number of Muslims in the US has increased by 40% in just five years -- between 2010-2015 -- while in the same period the non-Muslim population of the US has grown by only five percent. This means that the Muslim population is growing almost eight times faster than the non-Muslim population in the US.

As an adult, in the Muslim world, I came to hear verses and hadiths frequently used by extremists and carved into their minds. To them, these are the true instructions and predictions of the most powerful being. Those Muslims strongly believe that these verses and hadiths (sayings of Muhammad) will come true because they are issued by Allah (God) or by his messenger, Muhammad. Allah, for instance, says in the Qur'an Chapter (9:33) sūrat al-tawbah (The Repentance):

"It is he (Allah) who has sent his Messenger with guidance and the religion of truth (Islam), in order for it to be dominant over all other religions, even though the Mushrikoon (disbelievers) hate it."

A popular hadith is:

"Verily Allah has shown me the eastern and western part of the earth, and I saw the authority of my Ummah (nation) dominate all that I saw"

Some extremist Muslims believe that Allah and Muhammad predicted that they would rule over America even before America was discovered by Europeans. As a certain radical Muslim activist said on ABC news, "Indeed, we believe that one day, the flag of Islam will fly over the White House." He quoted a saying of Muhammad, from the Muslim scholar Al-Tabarani in the 10th-century. "The final hour," he said, "will not come until Muslims conquer the White House."

Many extremists also insist that Muslims do not need to be the majority in a country in order to take over the government: "A small portion of Muslims will rise and conquer the White House."

In the belief of fundamentalist Muslims, it is the obligation of every Muslim to pave the way for Islam to dominate America. They are encouraged to use various methods to ensure that this occurs -- these include force, violence and waging jihad (holy war).

Any action taken for the purpose of accomplishing that goal is applauded by Muslim extremists worldwide. Islamists and Islamist states, for instance, heavily praised, and quoted Louis Farrakhan when he predicted that, "God will destroy America at the hands of the Muslims. God will not give Japan or Europe the honor of bringing down the United States; this is an honor God will bestow upon Muslims."

There is historical proof of great nations succumbing to the ideals of extreme and determined radical groupsy. History has often taught hard lessons to powerful nations. Before one dismisses the danger America faces, take the time to learn about the past and just how easily and swiftly irreversible changes can happen: Russia in 1917, Germany 1933, Egypt in 1952, Iran in 1979, and so forth. Do not underestimate the ability of radical Islam to take over your government and impose Sharia law throughout this once free nation.

Americans should not think that they will somehow be an exception to that historical rule. This sense of immunity and dismissal led to the downfall of many countries throughout time. If Americans do not take the issue seriously, history may teach them the hard way that what once seemed impossible is here.