In the aftermath of the Brussels terrorist attacks, Ted Cruz sought to show he would be a president who could prevent such attacks on US soil by suggesting that police should patrol Muslim communities more heavily.
During an interview that aired on CNN, Mr Cruz bashed New York Mayor Bill de Blasio for calling off surveillance of the city's Muslim communities, even though that surveillance failed to surface a single lead for police.
"We need to empower law enforcement to patrol and secure Muslim neighborhoods before they become radicalized," Mr Cruz said in response to the attacks in Belgium. "We need to secure the southern border to prevent terrorist infiltration. And we need to execute a coherent campaign to utterly destroy Isis."
On Tuesday, bombings at Brussels' international airport and in the city's subway killed at least 30 people and injured about 230, according to the most recent report of the attacks. Isis has since claimed responsibility for the bombings.
Mr Cruz and fellow Republican presidential candidate Donald Trump repeated calls to prevent Muslims from entering the US and to keep close watch over those already in the country. Mr Trump went as far as to suggest torture should be used.
"Waterboarding would be fine," he said on NBC's Today. "If they can expand the laws, I would do a lot more than waterboarding."
Their Republican opponent, John Kasich, condemned such discrimination.
"In our country, we don't want to create divisions, where we say, 'You're a Muslim, we want to keep an eye on you,'" he said. "Just because you're a Muslim, it doesn't mean you're a radicalized Muslim who wants to destroy someone."
But Mr Cruz suggested that the methods used to monitor Muslims in the New York area -- like planting informants in mosques and infiltrating Muslim student groups -- should be considered across the country.
New York Police Commission Bill Bratton slammed Mr Cruz for his comments on Muslims, saying he took "great offense" from them.
"The statements he made today is why he's not going to become president of this country," Mr Bratton said. "We don't need a president that doesn't respect the values that form the foundation of this country."
In 2014, the New York Police Department acknowledged that such surveillance did not lead to any terror investigations. Police weren't able to find a single lead.
"I never made a lead from rhetoric that came from a Demographics report, and I'm here since 2006," said NYPD Assistant Chief Thomas Gulati in an Associated Press report. The Demographics Unit was the secret team that spied on Muslims communities in the city.
Mayor de Blasio ended the surveillance after he took office in 2014. Earlier this year, the NYPD settled two cases related to the surveillance.
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