The Bush administration has decided to postpone enforcement of new antiterrorism regulations that had threatened to block millions of Western Europeans and citizens of other developed nations from traveling to the United States. The rules that will require that citizens of 27 countries who do not usually require visas to visit the U.S. carry passports with text that can be read by computerized scanners at airports and other American border stations will go into effect one year later than planned, in Oct. 2004. Meanwhile, the Transportation Security Administration and the airlines will phase in a computer system next year called Computer Assisted Passenger Pre-screening System II (CAPPS II)”]