The executive order President Donald Trump signed Friday night was titled “Protecting the Nation from Foreign Terrorist Entry into the United States.” But by issuing a broad temporary ban on entries to the US from any national of 7 majority-Muslim countries, it turns out, the executive order is also “protecting” America from permanent residents of the United States.
Cases have been reported of permanent residents (green-card holders) being denied entry into the US at the border, or being refused to board planes, because they’re nationals of Iraq, Iran, Libya, Somalia, Sudan, Syria, or Yemen — countries that are covered by the 90-day ban Trump signed into effect on Friday night. The Department of Homeland Security confirmed to Reuters on Saturday morning that it was applying the ban to green-card holders. [More]
So that's what they're worried about. I want to know who gave half a million Green Cards to immigrants from place that are State Sponsors of Terror, failed states, and whatever Iran is at this moment.
The answer is probably Bush, Barack, and (in the case of Muslims with technical skills) Big Business.
However, the point about a Green Card is that it's a license issued by the Federal Government, and it can be un-issued by that same government.