The terror attack in Chattanooga, Tennessee carried out by an Islamic immigrant from Kuwait has cast new attention on the inability of the United States to properly screen the 100,000 Middle Eastern immigrants added to the United States each year, as well as the tens of thousands of additional Muslim youth admitted as foreign students.

In a comprehensive statement on the attack issued today, Senator Jeff Sessions (R-AL), Chairman of the Senate Committee on Immigration and the National Interest, explained why this incident, and many others like it, demand new immigration controls: “The events described above do not occur in isolation but are often part of broader networks, groups, and pockets of radicalization made possible by unwise immigration policy.”

Sessions listed a number of recent attacks carried out by immigrants voluntarily imported into the United States:

A 2005 Center for Immigration Studies highlighted 21 terrorists who immigrated to the United States and later applied for citizenship—20 of those citizenship applications were approved. Since just 2013, news reports have revealed a number of such individuals who were invited into the United States as part of our annual admission of one million new permanent residents, half a million foreign students, 70,000 asylees and refugees, 700,000 foreign workers, and 200,000 relatives of foreign workers. These individuals below did not hop a border fence or a dig a tunnel: they, like the 9/11 hijackers, applied for entry and were approved.

Here is the list provided by Sen. Sessions:

Based on these events, Sessions called for immigration curbs and a new emphasis on screening immigrants based on their capacity to assimilate. Broadening his critique, Sessions referenced Calvin Coolidge in explaining why he felt compassion and moderation demanded lower immigration levels after the four-decade immigration explosion experienced since 1970. Sessions’ push for immigration curbs contrasts with the push led by Sens. Chuck Schumer (D-NY) and Marco Rubio (R-FL) to triple the already historic admission of one million immigrants each year.

Sessions writes:

We should not admit people in larger numbers than we can reasonably expect to vet, assimilate, and absorb into our schools, communities, and labor markets. It is not compassionate but uncaring to bring in so many people that there are not enough jobs for them or the people already here. As Coolidge said: “We want to keep wages and living conditions good for everyone who is now here or who may come here.” Over the last four decades, immigration levels have quadrupled. The Census Bureau projects that we will add another 14 million immigrants over the next decade. It is not mainstream, but extreme, to continue surging immigration beyond all historical precedent. It is time for moderation to prevail, and for us to focus on improving the jobs, wages, and security of the 300 million people already living inside our borders.

The Tennessee shooter, according to his high school classmate, was very “devout” and his sister, “always talked about religion.”

According to United States Citizenship and Immigration Services (USCIS), one usually has to be 18 or older to be naturalized – suggesting that there were two prime opportunities for immigration authorities to have kept the Tennessee shooter out of the United States – first, when his family applied to immigrate they simply need deny the application, and second when he applied in-country to become a U.S. citizen authorities could have probed his radicalization and revoked his immigration status if they so chose.

More evidence will be needed to see what was known and when, but Sessions cited a statement from USCIS council President Ken Palinkas shining a light on how little investigating actually occurs:

“The President of the Citizenship and Immigration Services Council—which represents 12,000 United States Citizenship and Immigration Service Officers—has repeatedly alerted the deaf ears of Congress about this danger.”

In a recent statement, Palinkas declared: