The US knew for decades that terrorists could easily sneak a bomb into the global cargo system, yet didn't act because of pressure from shipping companies worried that a tighter security net would cost too much and cause too many delays. One shipping lobby has in fact spent some $60 million in the past two years opposing the requirement made in August that all cargo on passenger flights be screened.
The US now screens all packages before loading them on passenger flights originating in the US, but screening isn't required on cargo flights, nor on US-bound international passenger flights, reports the AP. The TSA considered requiring screening for all packages on all flights in 2004, but ultimately decided against it, writing that "a requirement to inspect every piece of cargo could result in an unworkable cost of more than $650 million" in the first year. The government wanted security, TSA said, "without undue hardship on the affected stakeholders." (More Yemen mail bombs stories.)