Well, that didnt take long. The definition is about to get broader, per WSJ:

In a statement that the State Department is due to release, which was reviewed by The Wall Street Journal, the 90-day visa moratorium extends beyond just citizens of Iraq, Iran, Somalia, Sudan, Syria, Libya, and Yemen.

It also applies to people who originally hail from those countries but are traveling on a passport issued by any other nation, the statement notes. That means Iraqis seeking to enter the U.S. on a British passport, for instance, would be barred, according to a U.S. official...."

http://www.wsj.com/articles/trump-visa-ban-also-applies-to-c...

Here's a non-paywall-ed version.

http://www.marketwatch.com/story/trump-visa-ban-also-applies...

Those nationals or dual nationals holding valid immigrant or nonimmigrant visas will not be permitted to enter the United States during this period. Visa interviews will generally not be scheduled for nationals of these countries during this period.

Huh. My next door neighbor is an American citizen, born in Iran. He left before the Shah was deposed. He owns a successful local company. Sounds like this would apply to him.

No wonder I haven't heard from them in a few months.

He's an American citizen so he can't be denied entry.

* As long as he is not a dual citizen.

That is very, very broad.

Quite. Historically, countries which build walls don't do so to keep people out, but to keep them in.