Trump's plan to keep Muslims out of the USA: Is his idea even legal?

Donald Trump is causing a stir with his idea to ban Muslims from entering our country. Critics are now blasting the Republican presidential candidate's proposal.

Is this legal? Meaning: Does Trump's plan violate the U.S. Constitution? We took it to a law professor to get an expert's take.

After the horror of the San Bernardino terror attack, Trump suggested a total and complete shut down of Muslims coming into the United States. That would include immigrants, of course, but also tourists and even Muslims who are U.S. citizens who travel out of the country. They wouldn't be allowed back in.

"I think it is probably patently unconstitutional.. can't think of another example that would be so obviously unconstitutional," said Associate Professor Steven Gonzales of Arizona Summit Law School.

In particular, Professor Gonzales says Trump's ban would violate the 14th Amendment to the Constitution -- equal protection of the laws and the 1st Amendment -- freedom of religion. And that's not all.

"And also there are international agreements the U.S. is party to.. it might violate those too if it is enforced," he said.

Muslims in the valley think Trump's idea is a bad one.

"It is very reminiscent of the Holocaust.. some of the same things that Hitler said then sounds extreme, but what he is saying is very extreme," said Arizona State University student Anisa Abdul-Quadir.

Meanwhile, a lot of people like Trump's plan. We see a lot of comments about it on Facebook.com/FOX10Phoenix.