Republican president candidate Dr. Ben Carson, a retired neurosurgeon who is polling in third place early Monday, said that the U.S. should not elect a Muslim president. Carson appeared on NBC's "Meet the Press" on Sunday and suggested that Islam is inconsistent with the Constitution.

Asked if the president's faith should matter to voters, Carson said that "it depends on what that faith is," he said. "If it's inconsistent with the values and principles of America, then of course it should matter. But if it fits within the realm of America and consistent with the Constitution, no problem."

Carson said that he does not regard Islam as consistent with the Constitution and that he "would not advocate that we put a Muslim in charge of this nation."

Last week, GOP front-runner Donald Trump made headlines after he declined to correct a supporter at a public event who falsely claimed that President Barack Obama was a Muslim. That same supporter also wanted to know how Trump planned to solve the "problem" of Muslims in the U.S. Although Carson and Trump were in different situations, Carson's comments about Muslims reflect a distinctly Islamophobic sentiment that has developed in the country, particularly following the rise of Islamic extremist groups such as ISIS.

A June Gallup poll found that 38 percent of Americans would not support a Muslim president. The only traits that proved less desirable, in fact, were being atheist (40 percent) and/or being socialist (50 percent). This thread of Islamophobia is largely reinforced by misunderstandings about Islam, often propagated through media, but it is also reinforced by the misguided comments of politicians such as Trump and Carson.

A number of Republican candidates—including Sen. Ted Cruz (R-Texas)—have spoken out against Carson since his appearance on "Meet the Press," and though his campaign spokesperson Doug Watts clarified that Carson "did not say that a Muslim should be prevented from running, or barred from running in any way," what he did say has still attracted widespread criticism.

Here's how people are reacting to Carson's Islamophobic comments.