Is a nuke-free world even possible?

Shortly before his death, Albert Einstein said that he had made "one great mistake" in his life -- facilitating the development of atomic bombs.

Shame on the USA for being the one country that has actually used those bombs in war.

Fortunately, President Obama seems to share Einstein's regrets about nuclear weapons. Speaking in Prague today, Obama promised to work towards "a world without nuclear weapons."

But he will do so cautiously, he explained: "Make no mistake, as long as these weapons exist, the United States will maintain a safe, secure and effective arsenal to deter any adversary and guarantee that defence to our allies, including the Czech Republic. We will begin the work of reducing our arsenal. To reduce our warheads and stockpiles we will negotiate a new Strategic Arms Reduction Treaty with the Russians this year."

Obama's approach is certainly wiser and more practical than the "bring 'em on" style of his predecessor.

And we certainly don't need all 5,914 warheads in our arsenals. (Talk about overkill!)

But I question whether a nuke-free world is even possible, given human nature. There will always be rogue states, with wreckless power-hungry leaders, who will want to have that edge, now that the technology exists.

For instance, would North Korea ever willingly end its nuclear weapons program?

Would China?

Would Israel?