The Chinese Exclusion Act was a United States federal law signed by President Chester A. Arthur on May 6, 1882. It was one of the most significant restrictions on free immigration in US history, prohibiting all immigration of Chinese laborers. The act followed the Angell Treaty of 1880, a set of revisions to the US-China Burlingame Treaty of 1868 that allowed the US to suspend Chinese immigration. The act was initially intended to last for 10 years, but was renewed in 1892 and made permanent in 1902. The Chinese Exclusion Act was the first law implemented to prevent a specific ethnic group from immigrating to the United States. It was repealed by the Magnuson Act on December 17, 1943.
They have that EXCLUSIVE power under the Constitution, and prospective immigrants and visitors are not protected by any element of the Constitution, including the 14th Equal Protection Clause.
Or the 1st Amendment.
Or, for that matter the 5th...as demonstrated by our hundreds of drone strikes overseas.
In the 20's, immigrants were screened for health and disease, ability to support themselves short and long term, AND Religion and country of origin.
Eventually, everyone who has an emotional reaction is going to have to walk back their statements.
What Trump proposes is 100% legal and Constitutional, should Congress pass it.
In fact, a President Trump could probably use Obama's EOs as precedent to do it via EO.
That's how Roosevelt did much of his security work during WW II.