Scholars in the United States also say a blanket ban on a person’s religion would be “unconstitutional”.
However other legal experts are less sure the High Court would reject the outspoken Republican’s aim to close US borders to the world’s 1.6 billion Muslims.
There is no legal or historical precedent and neither is there any Supreme Court case that clearly prevents a president or Congress from doing so.
Richard Primus, a constitutional law professor at the University of Michigan law school, said the only time religion is considered in cases was when it involved persecution and it was not a reason for banning someone.
He said: ”Saying ‘no Muslims allowed’ or ‘no Christians allowed’ would not be legal. It would probably be unconstitutional.”
Another scholar said the US courts would likely rely on constitutional provisions that protect religious freedom and prohibit discrimination to strike down a ban on Muslim visitors to the country.
Describing a hypothetical reaction to a period of intense racial unrest in the US, Vanderbilt University’s Suzanna Sherry, said: “Imagine that instead of banning Muslims, we banned blacks from any country.