CAIR's Hussam Ayloush
I recall vividly attending a town hall on violent extremism held at the Islamic Center of Orange County in January 2015. Hussam Ayloush, the Southern California director of CAIR, stated that by the government's own statistics "some twenty"American Muslims had gone to join ISIS. (He, of course. must have been omitting those the FBI stopped trying to leave the country.) He then asked why nobody was talking about the "thousands of American Jewish men who have gone to join the Israeli Defense Force killing the people of Gaza".
Of course, Ayloush's numbers were false at the time and have only grown since he made the comment. He did not include those arrested attempting to leave the US. (He also failed to note that we know of not one American Muslim who has gone to Syria or Iraq to fight against ISIS.) The entire issue is relevant given the controversy over President Trump's travel ban against citizens of seven Muslim-majority countries. Many of Ayloush's ilk are asking, "How many Americans have been killed in the US by people coming from those countries?"
If you want to be technical, the answer may well be zero so far. I will not attempt here to research and find every single case to refute that argument though I can cite one honor killing by an Iraqi man in the San Diego area who murdered his wife and tried to blame an Islamophobic intruder.
I could also point out that Libya, another country on the Trump list, is where four Americans were murdered during the attack on the Benghazi consulate.
However, I think the most important rebuttal would be to remind the reader of how many Muslims, either refugees, immigrants, converts, American citizens, or home-grown have been charged with terror plots/attempting to join ISIS or other terror organizations.
According to the Washington Post, 108 people have been charged with ISIS related plots. A total of 58 have been convicted. Keep in mind that ISIS is one of the newest terror organizations as compared to Al Qaeda.
"Federal prosecutors have charged 108 men and women around the country in connection with the Islamic State. So far, 58 have been convicted."
Apparently, that study does not include the Somalia-based terror organization, Al Shabaab. Several US-based Somalis have been charged with plotting to aid or join Al Shabaab, and several have successfully returned to Somalia to link up with them. Though national origin is generally not listed here, I would guess that several have as their national origin the 7 countries on Trump's travel ban. I would also wager that those from Minnesota are of Somali origin since that state has the nation's largest Somali population.
In the below article, 72 convicted of terror charges in the US are identified as originating from the 7 countries on the travel ban.
In addition, do you remember that recent knife attack at Ohio State University? The attacker was of Somali origin. Fortunately, none of the stabbing victims died.
Do these numbers represent a majority of US-based Muslims? Of course not. They don't have to. One man killed 49 people in a gay night club in Orlando. One married couple (the wife came into the US from Pakistan on a fiance visa) killed 14 in San Bernardino. Nineteen hijackers killed almost 3,000 on 9-11. The list goes on and on. The common thread was motive-jihad.