President George W. Bush, speaking at a mosque on Sept. 17, 2001: "The face of terror is not the true faith of Islam. That’s not what Islam is all about. Islam is peace."

Donald Trump, campaigning for president on March 9, 2016: "I think Islam hates us."

David Yerushalmi was living in an Israeli settlement near Jerusalem speaking on the phone with his father when the planes hit the towers on Sept. 11, 2001. "We got it wrong," Yerushalmi remembers telling his father. Before Sept. 11th, Yerushalmi thought terrorism was about nationalism, a fight over land. Afterward, he decided terrorism committed by Muslim extremists was driven by Islam itself -- and underpinned by Islamic Shariah law.  

So he packed up his family and moved to New York to become part of a fledgling community of conservatives who would come to be known as counter-jihadists. They had an uphill battle to fight: In the aftermath of Sept. 11, President Bush and most Americans, according to polls, did not equate Islam with terrorism. 

But 16 years later, even though there hasn't been another large-scale terrorist attack on American soil committed by a Muslim, America's perspective on Islam has changed -- evidenced most notably by the election of a president who believes the religion itself hates the country.

Yerushalmi is a big reason for this change of heart. He's a behind-the-scenes leader of the counter-jihad movement, filing lawsuits pushing back against the encroachment of Islam in the public sphere and crafting a series of anti-Sharia laws that Muslims and civil rights groups decry as Islamophobic.

"Do I think that the United States is weak enough to collapse either from a kinetic Jihad, meaning war, or even a civilizational Jihad that the Muslim Brotherhood talks about? No. At least not in my lifetime. But do I think it's an existential threat that allows for sleeper cells and the Internet-grown Jihadist that we see day in and day out wreaking so much havoc here and in Europe? Yes. Do I see it as a threat to our freedoms and liberties incrementally through their so-called civilizational Jihad where they use our laws and our freedoms to undermine our laws and our freedoms? Absolutely."

WNYC reporter Matt Katz speaks to Yerulshami about what he thinks is the creeping threat of Sharia law for the podcast "The United States of Anxiety" produced by New York Public Radio.