In the wake of the terrorist attacks in Paris and San Bernardino, California, Republican presidential candidate Donald Trump released a statement Monday that called for a “total and complete shutdown of Muslims entering the United States.”

The reason for his stance, according to the statement, is the “great hatred towards Americans by large segments of the Muslim population.” Trump cited a poll from the Center for Security Policy (CSP) that reported that of the 600 United States-based Muslims surveyed, 25 percent agreed that violence against Americans in the United States is justified as a part of the global jihad and 51 percent agreed Muslims in the country should “have the choice of being governed according to shariah.”

Political journalists have referred to the CSP poll as “shoddy”; the Southern Poverty Law Center has identified CSP’s founder, Frank Gaffney Jr., as “one of America’s most notorious Islamophobes.” In a 2011 column for CSP’s website, Gaffney wrote that the Muslim Brotherhood’s “civilization jihad” in the U.S. government and civil institutions is so pervasive, “a serious, sustained and rigorous investigation of the phenomenon by the legislative branch is in order.” Gaffney called for something akin to the Cold War-era’s House Un-American Activities Committee, which would examine and root out “anti-American – and anti-constitutional – activities.”

Trump’s statement went on to say that until the reason for the “hatred” held by Muslims is determined, “our country cannot be the victims of horrendous attacks by people that believe only in Jihad, and have no sense of reason or respect for human life.”

Trump’s dangerous rhetoric around immigration and his call to ban Muslims from entering the country has elicited swift responses from religious leaders and politicians alike. Former vice president Dick Cheney said, “[it] goes against everything we stand for and believe in.”

But Trump’s most recent remark comes on the heels of escalating anti-Muslim sentiment from others, including fellow presidential candidates.

Former New York Gov. George Pataki (R) recently tweeted: “We must declare war on radical Islam. @LorettaLynch I’m not edging toward violent speech, I’m declaring we kill them. Go ahead, arrest me.”

As reported by the New York Times, putting Trump’s proposed plan into practice would require an unlikely act of Congress sure to be invalidated by the Supreme Court as an overly restrictive immigration policy under the equal protection clause of the 14th Amendment. The specifics of Trump’s proposed plan to bar followers of the world’s fastest-growing religion from entering the United States are unknown. When pressed for details about who of the nearly 90,000 Muslims who immigrate to the United States each year would be banned, Trump’s campaign manager told the Associated Press the ban would apply to “everybody.” ​Trump later listed possible exceptions, including U.S. citizens traveling abroad, members of the U.S. military, athletes, and world leaders.