The First Amendment
Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the government for a redress of grievances.
The First Amendment was intended to prevent the federal government from declaring one version of Christianity as the official version of the national government. Period. It was never intended to allow the free exercise of any and every religion imaginable. As an extreme example, religions based on human sacrifice would not be protected. Under the First Amendment, everyone is free to speak on behalf of and to advocate for any religion they like, including a religion based on human sacrifice. However, they are not free to engage in religious practices or rituals that violate the laws of the land (such as, again, human sacrifice). All religious followers are still subject to the laws of the nation, the laws of their state, and the laws of their community. This is why polygamists and those communities which encourage child brides cannot use the First Amendment as a legal defense.
Clear so far? Seems simple enough, right? Here's the wrinkle:
Maliki Jurisprudence is a school of Islamic scholarship and law that serves as the formal legal system for dozens of Islamic nations. It is one of the five major schools of Shari'a. It is the school of law that every terrorist believes is the one true form of Islam. Under Maliki Jurisprudence, if a non-Muslim kills a Muslim then it is murder, but if a Muslim kills a non-Muslim then it is not murder. If a non-Muslim rapes a Muslim woman, the man is castrated and beheaded. The only testimony required to achieve such a conviction and penalty is the testimony of the victim. However, if a Muslim man rapes a non-Muslim woman then she can be beaten or stoned for causing him to be tempted. If a Muslim woman is raped by a Muslim man, she must find four witnesses who will testify against the man. If she cannot, then she can be beaten or stoned for causing him to be tempted. Naturally, infidelity and homosexuality are both punishable by execution. However, if a married Muslim man has sex with a non-Muslim woman, then under Maliki Jurisprudence it is not infidelity, which is why ISIS followers are free to own and use as many sex slaves as they can afford to purchase and maintain. Homosexuality is always prohibited and always punishable by death. Equally important to all of this, under Maliki Jurisprudence anyone claiming to be a Muslim who does not acknowledge the supremacy of Maliki Jurisprudence is not really a Muslim at all. Such a person is no different than any non-believer. This is why the vast majority of terror victims are Muslims. Those attacks which happen in non-Muslim countries, no matter how traumatic and tragic, are merely collateral damage in the war being waged by Maliki Jurisprudence to enforce its supremacy. This war of Maliki Jurisprudence for supremacy has been going on for about 1300 years and shows no sign of letting up any time soon. American involvement in this war is a very recent thing and from the perspective of Maliki Jurisprudence scholars, barely deserving of a footnote.
There are approximately 2 billion Muslims in the world. Around 25% of them regard the supremacy of Maliki Jurisprudence as a fact no different than the rising and the setting of the sun! Under Maliki Jurisprudence they are not required to obey the laws of any nation, state or community. They are only obligated to obey Shari'a as interpreted by Maliki ibn Anas. No, I am not exaggerating. There are at least 500 million Muslim men and women who believe they are not bound by any human laws other than those described and annotated by a Muslim scholar who lived in Medina in the 8th Century. Radical Islamic terrorists are not some kind of aberration, they are the enforcement arm representing 500 million Muslims living all over the world. This is why terrorism is so widespread and has no problem constantly recruiting young men and women. Under one of the leading schools of Islamic scholarship terrorism is not criminal, it is heroic.
Therefore, does anyone honestly believe the First Amendment of the Constitution grants followers of Maliki Jurisprudence the right to practice their religion freely and without interference within the United States of America? Because that is what we will wind up with if we accept a million or so refugees from the Syrian war. We will have communities that refuse to comply with the laws of our nation, that set up their own courts and legal systems, and who believe they can rape and murder their neighbors with no repercussions. In fact, there are many circumstances under Maliki Jurisprudence where murdering a non-Muslim man or raping a non-Muslim woman can be interpreted as an act of mercy.
This is not fearmongering. This is not paranoia. This is happening every single day in nations where Maliki Jurisprudence is the law of the land. This is also happening in European cities and nations with large concentrations of refugees in isolated neighborhoods. This is a simple reality of our world that everyone seems to be ignoring. Violent Muslim behavior against non-Muslims is not aberrant. It is allowed and in many cases actively encouraged by a large, persuasive, highly respected legal and academic school of Islamic thought.
The Maliki madhab
Maliki Fiqh Q&A
Wikipedia: Maliki Jurisprudence
Wikipedia: Maliki ibn Anas
Lampost Productions: Special Characteristics of the Maliki Madhhab
YouTube: Maliki Fiqh Online Academy