Could this be why we didn’t face a repeat of Madrid 3/11? From AP, :
More than 700 people were arrested on immigration violations and thousands more subjected to FBI interviews in an intense government effort to avert a terrorist attack aimed at disrupting the election.
As with past unrealized al Qaeda threats, law-enforcement officials said yesterday they don’t know for sure whether any of those arrests or interviews foiled an attack.
“It’s very hard to prove a negative,” said Michael Garcia, an Immigration and Customs Enforcement (ICE) official. “We did cases and operations for people we thought posed national security concerns. We didn’t arrest anyone who had a bomb.”
For example, ICE agents arrested a 23-year-old Pakistani man in late October who had entered the United States illegally through Mexico in 2000 and was working as a fuel-tanker truck driver with access to a major U.S. seaport. The man, who was not further identified, is charged with making false statements about how he entered the country, and remains under investigation for any links to terrorism.
He was one of the 237 persons arrested in October alone on immigration violations, for a total of more than 700 since the enforcement effort began last year, Mr. Garcia said. “It was a broad approach that led us to have a very disruptive effect, we believe,” he said.