In 2003, Elena Casacuberta, a postdoctoral student at the Massachusetts Institute of Technology (MIT) returned to Spain for winter break. Elena had renewed her work visa three times since she had been coming and going to the United States starting in 2000, so she did not anticipate any problems. Five months later, Elena was still in Spain, awaiting Visa Mantis security clearance. In the meanwhile, her NIH-funded research on the genetics of fruit flies was put on hold indefinitely.
In May 2004, Reza Chamanara, an Iranian postdocteral fellow in the department of mathematics at Indiana University , left for England to give a lecture and found himself blocked from returning to the United States Seven months later, university administrators were still unable to get an answer from the FBI as to why his visa renewal was being held up and whether he would be able to return.Add to this the example of Chinese students on F-1 visas, who are given single-entry six month student visas to enter the US. This basically means that if they ever have to travel outside the US to present a paper at a conference, they have to return to China and re-apply for a visa (unless all travel is compressed in a six-month window). [Update: As of June 20, 2005, they are now being issued 12 month multiple entry visas. Thanks, Dan Li]
Virginia Postrel points to a Steve Forbes editorial in Forbes magazine critiquing the government on this issue (Forbes is a conservative Republican; this is not a "red-blue" issue). She also quotes an Indian-born researcher colleague who says "For the first time, I feel like a foreigner in this country".
Sadly, even though I spend my time amongst the most diverse group of people one can imagine, I have to agree. For an entertaining and yet disturbing story of life in the US post 9/11, listen to Act I from this episode of This American Life.