It is no secret that terrorists want to blow up airplanes. Keeping explosives, no matter their form, off planes is crucial, but so is stopping terrorists using any means before they board aircraft. The United States, according to recent reports, is lagging on both fronts. The Department of Homeland Security, for example, continues to research liquid explosive detection systems and isn’t satisfied with the results. Finding the perfect system is a nice goal, having something in place now to thwart terrorist attacks is essential.

On the explosive detection front, DHS has spent $732 million this year on explosive deterrents and has tested several liquid explosive detectors in the past few years, but has been dissatisfied with the results, according to the Associated Press. Meanwhile, Japan has been using liquid detectors in its Narita Airport in Tokyo and demonstrated the technology to U.S. officials in January. The department called the technology “promising” and plans to test the equipment at six U.S. airports.

Is more testing necessary if the system is working successfully elsewhere? The same is true of small units that detect trace amounts of explosives. A 2002 report called for “immediate deployment” of the units, which cost $40,000, to major European airports, something that has yet to happen.

Endless research and delays in employing detection equipment, coupled with a request to take $6 million from the department’s science and technology budget that was earmarked for explosive detection technology to cover a shortfall in the protective service budget, have lawmakers questioning the direction of DHS. The department’s research division, called the Science and Technology Directorate, is a “rudderless ship without a clear way to get back on course,” members of the Senate Appropriations Committee wrote in a June report accompanying the department’s 2007 budget.

To get back on track, the directorate and the department must stop studying and start installing the best available explosive detection equipment. The recently renamed Office of Bombing Prevention could help, if its work is more focused and productive.

The department should also devote more attention to assessing airline passengers. Using techniques from Israeli airports, screeners at Dulles Airport, outside Washington, focused on passengers, not their baggage. They looked for signs, such as failure to make eye contact, clenched fists and sweating, that passengers were working too hard to act normal. Although no terrorists were caught, the new system found people carrying drugs, using forged visas and other things they wanted to hide.

The techniques, which were tried at Dulles beginning in 2003, are being introduced at other airports, but the man who oversaw the project for the Transportation Security Administration is not confident it will be allowed to work. “Terrorists will always come up with something new,” Scott McHugh told The New York Times. “As long as we keep looking for things from the last plot, we’re inconveniencing 99.99 percent of the people with no real benefit.”

Deterring terrorists without bringing air travel to a halt is a difficult balancing act. Because there have been no attacks using planes since 9/11, the balance may be right, but there are growing indications that better screening is needed to stay ahead of terrorists as upgrade their schemes.