As you stand in endless lines this holiday season, here's a comforting thought: all those security measures accomplish nothing, at enormous cost. That's the conclusion of Charles C. Mann, who put the T.S.A. to the test with the help of one of America's top security experts.

The U.S. Government Accountability Office recommends the Transportation Security Association strengthen its foreign airport assessment program and use its results to improve U.S. aviation security.

Adam Segal, author of "Advantage: How American Innovation Can Overcome the Asian Challenge," discusses the policy changes needed to achieve the Chinese ambition to move from a model of "made in China" to one of "innovated in China."

In the autumn of 2010, the Transportation Security Administration (TSA) began deploying new technologies and procedures for screening passengers at airport checkpoints. Reports of negative public reaction to some of these changes have prompted intense congressional interest in TSA passenger screening. This report addresses some of these concerns.

New screening measures at U.S. airports are being called overly intrusive by some passengers and civil rights groups. National security experts advise using a system that relies more on intelligence, behavioral profiling, and empowering passengers.

Amity Shlaes discusses the conflict between security and freedom represented by airport screening measures.

Failures to stop the recent U.S. airliner bomb plot and the destruction of a CIA base in Afghanistan illustrate inherent problems in intelligence gathering, and al-Qaeda's impenetrability, says CFR's Richard K. Betts.

President Obama has called for tweaks to the way terror suspects are monitored, but some observers wonder whether the changes will be sufficient to prevent a repeat of the Christmas Day terror plot.

CFR's Edward Alden says U.S. response to recent air-security failures should be to improve existing measures that identify genuine threats instead of imposing "knee-jerk initiatives that look tough" but may be less effective.

Repercussions of the failed Christmas Day bombing continue, with policy debate focused on Yemen as a new al-Qaeda front and possible delays shuttering Guantanamo Bay.

Throngs of holiday travelers push the limits of already taxed security and air traffic control systems, making for an unsavory Thanksgiving recipe.

Sebastian Mallaby, director of CFR’s Center for Geoeconomic Studies, says the skewed governing securities ratings agencies is partly to blame for stock market turmoil.

New technologies hold promise for improving airport security, but against growing threats, a holistic, “layered” approach is needed.

George Naccara, director of security at Boston's Logan Airport, discusses the myriad threats American airports face and some of the measures designed to keep them safe.

Paul Ekman, professor emeritus of psychology at the University of California at San Francisco, explains Screening Passengers by Observational Techniques, or SPOT, a form of behavioral observation that could help secure U.S. airlines.

The air travel system remains one of the most high-profile targets for terrorists. This backgrounder examines efforts to improve aviation security since the 9/11 attacks.

The central finding of this report is that federal government has had a naïve view of what the market is able to do when left largely on its own to protect critical infrastructure.