America's bomb-making process, brought to you by Rube Goldberg.

If the United States government were to resume building nuclear weapons today, the process would be a cross-country odyssey. The individual bomb parts would have to travel thousands of miles across the nation, with each journey being an invitation for a radioactive accident or a terrorist attack.

The process would probably begin in a boardroom at the Los Alamos National Laboratory in New Mexico. Some of the lab's more than 10,000 physicists would first create a basic plan for the new bomb. They would decide on the weapon's size, the materials to be used in its construction, and the exact process for how to catalyze its nuclear reaction. Then, scientists at Los Alamos and our second major design lab, in Livermore, Calif., would together make an exact blueprint of the bomb design. Computer scientists at both labs would run the design specifications through supercomputer modeling software to help polish them for maximum efficacy.

Then, the stage would shift to the Sandia National Laboratories outside of Albuquerque, N.M. Having received an electronic copy of the bomb's blueprint from Los Alamos, Sandia engineers would design everything else for the weapon, from its aluminum casing to its parachute to the high explosive charge needed to set off the nuclear reaction.

Next stop, via a high-security military aircraft, would be the Y-12 site in Tennessee, where engineers would begin building the uranium shell, or tamper, for the bomb. Then it's off, by heavily armed rail or truck convoy, to the Savannah River site in South Carolina. There, technicians trained in handling nuclear materials would add the tritium or deuterium composites that turn a plain old fission bomb into a massive thermonuclear fusion bomb.

The shell and its radioactive materials would then retrace their route westward by rail or truck, headed for the Pantex weapons plant outside of Amarillo, Texas. That plant would have already received the advanced electronics parts from the Kansas City factory that makes all the circuitry for nuclear weapons. At Pantex, technicians would rake plutonium and other weapons parts and assemble the live bomb.

But the journey wouldn't end there. The finished bomb would then be shipped from Texas to the Nevada Nuclear Testing Site, where it would be buried deep in the earth, covered with a plug of thousands of tons of cement, and ignited--in contravention of the Nuclear Test Ban Treaty. Assuming the explosion went as expected, engineers at the Nevada site would give the go-ahead for full-scale production of the bombs at Pantex. As each weapon was finished and certified in Texas, it would then head by rail, plane, ship or truck to its (perhaps temporary) resting place--military bases around the world.

Producing a weapon using eight different sites would require us to regularly ship radioactive materials across the country, within a few miles of large population centers. That greatly increases the risk, and the potential consequences, of an accident or a successful terrorist attack. Though there's reason to believe that nuclear materials are inadequately protected within our nuclear facilities, they're likely to be even more exposed when traveling on open public roads.