Sounds like Anarchists were the Terrorists of the early 20th century; unless contained they would bring about the end of Western Civilization as we know it. I wonder what new amorphous threat we will worry about a hundred years from now.

From Part 1a, Formal Charges:

We are informed and believe and charge that Professor Albert Einstein is inadmissible to the United States on the following grounds

a) Albert Einstein believes in, advises, advocates or teaches a doctrine which, in a legal sense, as held by the courts in other cases, “would allow anarchy to stalk in unmolested” and result in “government only in name.”

b) Albert Einstein advises, advocates or teaches, and is a member of _and_ affiliated with groups that are in “militant” and admittedly ”illegal” opposition to the most fundamental principle of organized government.

Edit: It has been pointed out that these formal charges are made by The Women Patriot Corporation, not the FBI.