Story highlights

Frank Gaffney Jr. founded the Center for Security Policy in 1988

The Southern Poverty Law Center calls Gaffney "one of America's most notorious Islamophobes"

Gaffney on CNN: "People who wish to suppress us... are playing into the hands of those who are, in fact, our enemies."

CNN  — 

In his call Monday for a “total and complete” ban on the entry of Muslims into the United States Donald Trump cited poll data from a fringe think tank operated by a man the Southern Poverty Law Center calls “one of America’s most notorious Islamophobes.”

Frank Gaffney Jr. founded the Center for Security Policy in 1988 after spending more than four years as a senior official in President Ronald Reagan’s Defense Department. In recent years, he has become a prominent figure in right-wing politics, co-authoring a book that warns of the “creeping” influence of Sharia law while producing and promoting an assortment of anti-Islamic conspiracy theories.

The online survey used by Trump in his statement claimed “a majority (51%)” of Muslims living in the U.S. believe they “should have the choice of being governed according to (Sharia).”

One-quarter of those polled “agreed that violence against Americans here in the United States is justified as a part of the global jihad.”

RELATED: Trump calls for travel ban on Muslims

Gaffney is well-known to anti-extremist groups, like the Southern Poverty Law Center, which plans to add his group to its “hate list” for 2016.

“He’s accused a Hillary Clinton adviser (Huma Abedin) of being a secret agent of the Muslim Brotherhood, he’s claimed (anti-tax activist) Grover Norquist is a secret agent, he believes all kinds of conspiracy theories, he’s a birther,” Heidi Beirich, director of the Southern Poverty Law Center’s Intelligence Project, told CNN. “It’s really, really troubling.”

Asked during a Tuesday interview with Don Lemon on “CNN Tonight” if he agreed with Trump’s plan to temporarily halt the immigration of Muslims into the country, Gaffney said, “I think that we have enough jihadists in America at the moment, plenty actually, and too many, and the idea of importing still more willy-nilly seems to me to make no sense at all.”

Gaffney has long been preoccupied with the Muslim Brotherhood, an Islamist political and religious group most prominent in Egypt.

“We know for a fact that the Muslim Brotherhood has as its mission the worldwide imposition of Islam’s toxic, brutally repressive and anti-constitutional supremacist doctrine known as (Sharia),” he wrote in a 2013 column accusing Republican Sens. John McCain and Lindsey Graham of providing “bipartisan political cover to the Islamists’ efforts to takeover (Libya and Syria.)”

Three years earlier, during an appearance on CNN, Gaffney argued that the goal of most “Muslim-American organizations” and mosques “is to destroy western civilization from within.”

He was barred in 2011 from participating at the Conservative Political Action Conference after accusing attorney Suhail Khan and Norquist of “credentialing the perpetrators of this Muslim Brotherhood influence operation.”

Gaffney has also pushed a theory, supported by what he described in 2009 as “pretty compelling circumstantial evidence,” that Saddam Hussein’s Iraq was “involved” in the 1993 attack on the World Trade Center and the 1995 bombing of the Alfred P. Murrah Federal Building in Oklahoma City.

Trump, however, praised the group during a rally in South Carolina on Monday night as he outlined him proposed ban on Muslims.

“Very respectable group, who I know, actually,” Trump said.