New York Times: Even though much R&D has been conducted to develop a scanner that detects dangerous items in shoes while they are being worn, US airports are still requiring airline passengers to remove their footwear at security checkpoints. X-ray machines have no trouble detecting metal, but no current technology can detect all of the different chemical compounds, liquids, and gels that can be used as explosives. However, many security experts believe that rather than focusing on intercepting items such as guns, knives, and explosives, the Transportation Security Administration should be focusing on stopping people, writes Ron Nixon for the New York Times. Israel, for example, uses interviews and profiles of passengers to look for potential terrorists.