The leaked OSI report tells of a pattern: ignorance of their entry, toleration of their presence (and a welcome for some who were deemed valuable such as those involved in rocket design and research), followed eventually by quite vigorous official action.
Alas, history tends to repeat itself. The pattern of immigration and occasional tolerance by the U.S. authorities was followed for suspected war criminals from modern-day conflicts - from Yugoslavia, Guatemala, El Salvador, Argentina, Rwanda and elsewhere.
Nowadays U.S. immigration authorities are pursuing over 1000 cases. Unlike the UK which has almost state of the art laws which are never used; the US has criminal laws which are full of holes - yet ICE and DOJ are effective in using prosecutions for visa fraud as an 'Al Capone' alternative. (If you've ever wondered why, when flying into the U.S., you have to fill in that green visa card stating that you're not a Nazi, terrorist, or genocidaire - wonder no longer). The answer for the U.S. is a crimes against humanity act, and reforms to the War Crimes Act to allow for an element of extra-territorial jurisdiction. The answer for the UK is greater use of criminal prosecutions and less reliance solely on administrative processes on the suspects found here.
