Spare and sterile, with computer screens pointing in every direction, the room looks like a high-tech conference center, far more NASA than City Hall.
Not only will the three-level center serve as the entry and screening point for visitors.
Under the new system those more thorough searches will be carried out earlier, at the main screening point.
It is important, Lieutenant Nichols said, that the new center will provide some distance between the screening point and entry into the Capitol itself.
Eventually, Mr. Hoyer said, a new visitors' center will be built on the Capitol grounds, designed to enhance security by serving as a central screening point.
Screeners need the boarding pass at the main screening point, rather than the gate, because the pass indicates whether travelers have been selected for more scrutiny.
Proponents of prostate screening point to the success of routine mammography for women over 50 in greatly reducing the breast-cancer mortality rate.
"Almost all of the pancreatic cancers have mutations in KRAS, so that's an ideal situation from a screening point of view," Dr. Vogelstein said.
As the New York City Council learned tragically last year when a councilman was killed after he helped get his killer around the screening point, the point of security is not to make sure that people are carrying the correct form of identification.
On the other hand, cancer experts in favor of screening point out that prostate cancer death rates among American men have dropped decisively in the last decade, following the introduction of the P.S.A. test.
