Oppenheimer knew the dangers of the nuclear bomb after he helped to build it, and he warned us back then:

(c) 2001 The Washington Post Company

OPPENHEIMER'S WISDOM

First Line Against Terrorism
By Kai Bird and Martin Sherwin

Wednesday, December 12, 2001; Page A35

In the spring of 1946, J. Robert Oppenheimer was asked in a closed
congressional hearing room "whether three or four men couldn't smuggle
units of an [atomic] bomb into New York and blow up the whole city."
The father of the atomic bomb answered, "Of course it could be done,
and people could destroy New York."

When a nervous senator then asked how such a weapon smuggled in a
crate or even a suitcase could be detected, Oppenheimer quipped, "With
a screwdriver." A few years later, he persuaded the Atomic Energy
Commission to write a top secret study on the dangers of nuclear
terrorism. The document, known as the "Screwdriver Report," remains
classified to this day. Our leaders realized then that there was no
defense against such an attack and, because we were defenseless, chose
to play down its possibility.

But on Sept. 11 Islamicist terrorists used knives and box-cutters to
turn commercial aircraft into weapons of mass destruction. And then
there was anthrax. The next time they could use spent nuclear reactor
fuel wrapped in explosives. And if they are determined to sacrifice
their own lives, the assassins will achieve a high degree of success.

Oppenheimer understood a half-century ago that by unlocking the
power of the atom he and his colleagues had suddenly made the world a
smaller place. That's why in 1946 he proposed banning nuclear weapons.

The globalization of science and technology has now reached a point
where weapons of mass destruction really can be wielded by a handful
of individuals. In such a world, our military prowess is our very last
line of defense.

In 1948 Oppenheimer observed that nuclear weapons -- born in secrecy
and designed as "unparalleled instruments of coercion" -- were by
definition antithetical to a free society. And so paradoxically he
insisted that even a nuclear-armed America must nevertheless remain
loyal to two mutually interdependent ideals, the minimization of
secrecy and coercion: "We seem to know, and seem to come back again
and again to this knowledge, that the purposes of this country in the
field of foreign policy cannot in any real or enduring way be achieved
by coercion."

Kai Bird, a fellow at the Smithsonian's Woodrow Wilson International
Center for Scholars, and Martin Sherwin, a professor of history at
Tufts University, are writing a biography of J. Robert Oppenheimer.