The government’s terrorist screening database flagged Americans and foreigners as suspected terrorists almost 20,000 times last year. But only a small fraction of those questioned were arrested or denied entry into the United States, raising concerns among critics about privacy and the list’s effectiveness. A range of state, local and federal agencies as well as U.S. embassies overseas rely on the database to pinpoint terrorism suspects, who can be identified at borders or even during routine traffic stops. The database consolidates a dozen government watch lists, as well as a growing amount of information from various sources, including airline passenger data. The government said it was planning to expand the data-sharing to private-sector groups with a ‘substantial bearing on homeland security,’ though officials would not be more specific. Few specifics are known about how the system operates, how many people are detained or turned back from borders, or the criteria used to identify suspects. The government will not discuss cases, nor will it confirm whether an individual’s name is on its list. Slightly more than half of the 20,000 encounters last year were logged by Customs and Border Protection officers, who turned back or handed over to […]