Don't blur nuclear line.

Byline: The Register-Guard

A $15.5 million item could prove to be the most consequential and costly expenditure in a proposed $400 billion military budget. The Senate Armed Services Committee has approved funds to research a new bunker-busting nuclear weapon. It also supports lifting a 10-year-old ban on the study of low-yield nuclear bombs. The world does not need a new generation of nuclear weapons, and the United States needs it even less.

Low-yield nuclear weapons are classified as those with an explosive force of 5 kilotons or less; the bomb that destroyed Hiroshima in 1945 was a 15-kiloton device. The smaller weapons are sometimes called "battlefield" nuclear arms - meaning that unlike the city-flattening multi-megaton missiles in the nation's strategic arsenal, they could be used much like conventional weapons to strike specific military targets.

Proponents of adding low-yield nuclear weapons to the United States' arsenal have advanced their arguments for at least a quarter-century. The idea dates back to the Reagan-era concept of a "winnable" nuclear war. At that time, Keith Payne was a leading exponent of the notion that nuclear weapons could be used in warfare ending in something short of an apocalyptic exchange. As the Pentagon's deputy assistant secretary of defense for forces policy, Payne is lodged in the department where weapons for a winnable nuclear war would be developed, and his long-held goal is coming within reach.

The United States resisted the development of battlefield nuclear weapons throughout the Cold War, and for good reason. Since the dawn of the nuclear era, a clear demarcation has existed between nuclear and conventional weapons. Nearly every nation possesses conventional weapons, and they're used without restraint in dozens of wars around the world. Nuclear weapons are possessed by only a handful of countries, and their use has been successfully restrained by an appreciation of their destructive power. The introduction of low-yield nuclear arms would blur the distinction, making it easier for nations or their armies to cross the nuclear threshold.

The end of the Cold War further weakened the rationale for low-yield nuclear weapons. The United States and Russia have spent the past decade negotiating mutual reductions in their nuclear arsenals; both nations have more than is needed for the purposes of deterrence. In 1993, Congress approved the Spratt-Furse Amendment - named for its sponsors, Reps. John Spratt, D-S.C., and Elizabeth Furse, D-Ore. - banning research on tactical nuclear warheads.

Since then, the United States has demonstrated a decisive superiority in conventional weapons, most recently just weeks ago in Iraq. No nation can match either the explosive force or the precision of American munitions. The addition of low-yield nukes would not remedy a deficiency in the U.S. arsenal.

Payne and members of the Senate Armed Services Committee believe that precisely targeted, low-yield nuclear weapons could prove useful against enemy missile launchers or underground bunkers. Using such weapons in Iraq, however, would have been a ghastly mistake, given the inability to date to locate the weapons of mass destruction whose supposed existence gave urgency to the attack. Using nuclear weapons to destroy nuclear weapons programs in North Korea or Iran would be widely seen as reckless and hypocritical.

An even more serious concern is that other nations might seek to develop battlefield nuclear weapons of their own. If the United States demonstrates that it regards low-yield nukes as little more than a supplement to conventional weapons, others would follow. Nuclear weapons testing, suspended since 1992, would resume. The line between nuclear and conventional warfare would become blurred - a line that has probably already prevented a nuclear exchange between India and Pakistan.

The United States, with the world's most powerful nuclear arsenal and its best conventional weapons, has the most to lose by creating an in-between category. No nuclear weapon has been used for nearly six decades, because nuclear war has been regarded as unthinkable. Making it less so endangers everyone. The Senate Armed Services Committee has made a dangerous mistake. The full Senate should reverse it.