How were Donald Trump's 2015 comments about Muslim immigrants unconstitutional?

Question

A 2015 campaign press release from Donald Trump, back then the leading contender to become the Republican party’s nominee for US presidential candidate, called to ban Muslims from entering the United States:

"Donald J. Trump is calling for a total and complete shutdown of Muslims entering the United States until our country's representatives can figure out what is going on."

White House press secretary Josh Earnest responded to this during an official White House press briefing:

"The Trump campaign, for months now, has had a dustbin of history-like quality to it, from the vacuous sloganeering to the outright lies to even the fake hair — the whole carnival-barker routine [...] It’s morally reprehensible, it runs counter to the Constitution and it has consequences for our national security [...] The fact is what Donald Trump said yesterday disqualifies him from serving as president"

Was Josh Earnest's statement that denying entry to the United States based solely on religion would be against the constitution correct?

And was Josh Earnest in his function as a representative of the White House allowed to criticize party nominee contenders that way?

Answer 1

The premise of your question was faulty prior to the edit; the Constitution protects the rights of every individual within the jurisdiction of these United States from infringement by the Federal, State, and Local Governments. There is not a prerequisite that an individual be a citizen to have their rights protected, though there may be a few more hoops for them to go through to exercise those rights. Yes, there are certain rights that are restricted to citizens, like voting.

Most of the 'unConstitutional' determinations about Trumps statements are based on an obtuse expansion of his statements beyond what he said. In referencing actions taken by FDR to limit the immigration of Germans, Italians, and Japanese, he opened himself up to a connection to the Japanese internment. Past that, there are current Treaties and other associated agreements between these US and other nations regarding immigration policies. It would take an act of Congress, adjusting legislation, to modify who is allowed into these United States.

On the 'right to disqualify,' they can't. They are just calling his character into question giving his prejudicial statements. The administration however, through Josh Earnest, is free to discredit or judge Trumps statements publicly. There is a legitimate concern that his expressed desire of keeping out all muslims can be used as a propaganda or recruiting device. However, the shortcoming of that concern is that there is already a stated intention to kill us; hiding from that reality just leaves these United States unprepared to provide a defense.

Answer 2

A new answer since this question has taken on renewed importance.

There is a misconception here. Banning a whole community is not Unconstitutional. The Constitution only applies to US citizens, and to non-citizens after they have passed the immigration checkpoint. One can certainly disagree whether this is fair and whether it should be done this way, but this is simply the way it is, affirmed by many Supreme Court decisions.

As a matter of fact, the US had laws banning people from certain countries in the past, and they were upheld by the Supreme Court. The Chinese Exclusion Act, which was in force from 1884 to 1921, comes to mind. Also the post-1921 quota system that heavily favored European immigrants.

However, today, banning a community based on country of origin is a violation of the Immigration and Nationality Act of 1965. 8 U.S. Code § 1152 (a)(1)(A) spells it out (emphasis mine):

Except as specifically provided in paragraph (2) and in sections 1101(a)(27), 1151(b)(2)(A)(i), and 1153 of this title, no person shall receive any preference or priority or be discriminated against in the issuance of an immigrant visa because of the person’s race, sex, nationality, place of birth, or place of residence.