Bunker buster is back.

Byline: The Register-Guard

The U.S. nuclear arsenal includes 5,685 warheads atop land- and sea-based intercontinental ballistic missiles, 2,045 nuclear bombs and cruise missiles carried by B-2 and B-52 bombers and 1,610 tactical nuclear weapons. As many as 10,000 warheads are held in reserve in underground bunkers scattered across the nation - in case the first 9,340 nukes have left any stone unburned.

But almost all of that apocalyptic ordnance suffers from the same liability: overkill. It's just too dang destructive to deploy in the constrained conflicts typical of modern U.S. warfare. It's only good for keeping other traditional nuclear adversaries in check. For all intents and purposes, the big boomers have become ceremonial doomsday devices.

The Bush administration is interested in something a little more practical. Enter the Robust Nuclear Earth Penetrator.

Not only does the RNEP sound like it could be manufactured by Tonka rather than Raytheon, it also comes with a cute nickname: bunker buster. With a few modifications, an existing 1.2-megaton B83 nuclear bomb could be made to burrow deep underground before exploding. That would give the U.S. military the capability to take out hardened and deeply buried targets such as command bunkers or underground storage sites containing chemical or biological agents.

The message would be clear: Listen up, Iran, North Korea, al-Qaeda. You can run, but you cannot hide from the Robust Penetrator.

But that's exactly where the biggest problems with the bunker buster begin. For U.S. enemies to regard the bunker buster as a credible threat, U.S. nuclear policy has to embrace pre-emptive, first-strike use of the weapon. That bolsters arguments within Iran and North Korea to continue "defensive" nuclear weapons development, negating vital U.S. efforts to stop the spread of nuclear weapons.

More important, the public is being misled into believing the bunker buster would be a surgical strike smart bomb, capable of cleanly taking out Osama bin Laden's underground command post with minimal U.S. casualties. Nothing could be fur- ther from the truth.

The B83 is the largest nuclear weapon in the U.S. arsenal, and nearly 100 times more powerful than the atomic bomb used on Hiroshima. No nuclear earth penetrator can plunge deep enough to contain the nuclear fallout. Even the strongest casing will crush itself by the time it penetrates 10 feet to 30 feet into rock or concrete. A recent study by the National Academy of Sciences pointed out that fallout from a B83 bunker buster explosion could spread over 1,000 miles and kill up to a million or more people.

President Bush has requested $4 million in fiscal year 2006 to study the bunker buster and an additional $4.5 million to modify the B-2 bomber to carry the weapon. No harm in a study, administration supporters insist.

What study? The RNEP program is anything but conceptual. The Department of Energy's 2005 budget included a five-year projection totaling $484.7 million for weapons laboratories to produce a completed warhead design and begin production engineering by 2009. Thankfully, that funding was zeroed out in 2005 by the Republican chairman of a House appropriations subcommittee.

But like the vampire Lestat, the bunker buster is back, and it's time for Congress to drive a stake through the heart of this dangerous, unnecessary program once and for all. The notion that Americans will be safer in a world in which their own government threatens pre-emptive nuclear strikes is utterly incomprehensible.