You're asking the wrong question. Confining our security efforts to the airport checkpoint is like making sure you have a lock on your bathroom door to protect yourself against a home invasion. Here's a better question: Where do you think terrorist efforts are better stopped?

a) During terror-plot planning stages, using sophisticated intelligence tactics to identify and stop would-be terrorists at their residences, weeks or months before any planned event, OR
b) During the terror-plot execution phase, using high-school dropouts to harass, threaten, and intimidate everyone who passes through an airport checkpoint just minutes before a planned event

The safety and security of the travelling public starts long before the checkpoint, and the bulk of our effort should be directed to effective and proven intelligence techniques. Large-scale terrorist attacks (like 9/11) require years of planning and involve many people. As the terrorist plot grows in size and scope, so does our ability to track down the would-be perpetrators with traditional sleuthing and counter-intelligence. Unfortunately, these "behind the scenes" efforts do little to provide the security theater that TSA is so dependent on.

The idea that most or all of our security comes from actions we take at the checkpoint will never succeed. At best it slows travel to a miserable pace; at worst, it's a blatant violation of civil liberties and constitutional rights.

Security is a trade-off. We trade time, money, convenience, liberty, and privacy to gain security. Unfortunately, the TSA is costing us all of those things but providing little actual security. The primary goal of the TSA is not to keep us safe; instead, by examining their actions, you will find that the ultimate goal of the TSA is to ensure they are not blamed for any terrorist attacks that do succeed. It's what we call security theater: ineffective security techniques that are largely for show.

Effective security at the checkpoint should really be focused on catching the type of threat that intelligence is least capable of detecting: the lone wolf with a crazed plan. This sort of terrorist operates alone, has little or no planning, and is mostly likely using rudimentary weapons like a gun or knife. A simple bag x-ray and WTMD, with a localized wanding and/or pat-down for any alarms, is sufficient here. Ditch everything else, including the shoe carnival, the liquid ban, harrassing interrogations, and most importantly, the body scanners.