Rail gun: too much of a jolt to the arms race?

The Navy plans to show off -- with no live firing -- its latest whiz-bang weapon, a "Star Wars" rail gun, to the public soon at its San Diego base.

The weapon, developed by San Diego-based General Atomics and BAE Systems, uses a powerful electromagnetic pulse to hurl a 23-pound projectile up to 100 miles at a speed as high as Mach 7. Each projectile costs about $25,000, which is 1 percent of the price of a conventional ship-borne missile, the Navy said.

The Navy sees the weapon as a major force multiplier. A ship can carry far more rail gun projectiles than ballistic (unguided) missiles.

Now, of course, local defense industry boosters are doubtless pleased. And any military officer worth his or her salt favors, as a general rule, force multiplication.

However, the United States -- even with proposed Pentagon cuts -- still has the strongest Navy in the world. Is the proposed benefit actually cost effective? Expending very costly ballistic missiles might be seen as wasteful, but that depends on the probability of their actually being used as anything more than a deterrent.

On the other hand, with the substantial reduction in force coming for women and men in uniform, it seems sensible to at least partly compensate with weapons that magnify firepower.

Nevertheless, merely because defense contractors and admirals say something is a great idea, doesn't necessarily make it so. After all, won't Russia, Iran, North Korea and other nations, such as Israel, England and Japan, attempt to develop such a weapon? Might we unnecessarily be stimulating an arms race?

The technology is no doubt secret, but the "Lorentz force" the weapon uses is very well understood by engineers and physicists. If Iran and North Korea can figure out the rudiments of nuclear arms design, it seems plausible that they can dope out the basics of rail guns, which, we guess, get their pulse of energy from a powerful laser, and laser technology is quite well understood.