On a mission to slow or stop his government's march to war, Kennedy issued the stark warning today in a Los Angeles Times opinion article he wrote about administration plans to use nuclear weapons against Iraqi leader Saddam Hussein.

"By raising the possibility that nuclear weapons could be part of a first strike against Iraq, the administration is only enhancing its reputation as a reckless unilateralist in the world community," Kennedy wrote.

"This policy also deepens the danger of nuclear proliferation by, in effect, telling non-nuclear states that nuclear weapons are necessary to deter a potential U.S. attack and by sending a green light to the world's nuclear states that it is permissible to use them.

"Is that the lesson we want to send to North Korea, Pakistan and India, or any other nuclear power?"

The debate began a year ago with the leak of the Pentagon's "Nuclear Posture Review," which recommended consideration for using nuclear weapons as part of a pre-emptive strike. President George W. Bush has not commented on the issue.

Concerns have been heightened in recent days by reports that U.S. military planners have been actively studying lists of potential Iraqi targets and considering the use of so-called "bunker-buster" nuclear weapons against deeply buried military targets.

Bush administration officials argue that due to the way Saddam hides his weaponry underground, nuclear arms may be the only method of destroying those targets. Some officials have argued that the blast and radiation effects of such strikes would be limited.

But critics say a bunker-buster nuclear strike could involve a huge radiation release and dangerous blast damage.

They also argue that using a nuclear weapon for such purposes in Iraq would encourage other nuclear-armed countries to consider using those weapons in more kinds of situations, undermining 50 years of efforts to contain the spread of nuclear weapons.

The White House has refused to comment on the Pentagon leaks, other than to say: "The United States reserves the right to defend itself and its allies by whatever means necessary."

Kennedy sits on the Senate armed services committee and has sat in on several classified briefings related to Pentagon planning and Iraq. And in penning his opinion article, he appears extremely agitated about the issue.

"A dangerous world just grew more dangerous... That the administration is contemplating the pre-emptive use of nuclear weapons in Iraq should set off alarm bells that this could not only be the wrong war at the wrong time, but it could quickly spin out of control."

Kennedy said Bush could have clarified these reports in his State of the Union speech Tuesday, but chose not to.

"Using the nation's nuclear arsenal in this unprecedented way would be the most fateful decision since the nuclear attack on Hiroshima," he wrote, calling even the consideration of using nuclear power against Iraq "preposterous."

Kennedy argued that nuclear weapons need to be kept in a military category all their own, to be used only if "the existence of the nation is threatened."

He argued America can, if it chooses, win a war in Iraq with sophisticated new weapons at its disposal, but without tapping the nuclear button.

"The president has not made the case that the threat to our national security from Iraq is so imminent that we even need to go to war — let alone let the nuclear genie out of the bottle."

Kennedy also predicted that U.S. use of nuclear weapons in Iraq would bring a "near total breakdown" in relations between the U.S. and the world community, leading to a massive rise in anti-Americanism and even "sympathy for terrorists who seek to do us harm."