On 11 occasions over the past nine months, the U.S. and allies cooperating in the Proliferation Security Initiative (PSI) have successfully prevented the spread of nuclear, chemical or biological weapons or related items. At least two of those incidents involved Iran, two involved North Korea and another involved an unidentified third country, State Department spokesman Richard Boucher confirmed. Tuesday marked the second anniversary of the PSI, a project launched by President Bush during a 2003 visit to Krakow, Poland. With a focus on stopping and searching ships, planes, trains or trucks, the PSI aims to prevent terrorists and rogue states...