Why Worry About Nuclear Weapons?

A security studies professor suggests alarmism is more dangerous than nuclearism

With all the fuss over the Iranian nuclear threat, there are a lot of questions: Does the regime want weapons? How close is Iran to getting the bomb? What can we do to prevent it? But security studies professor John Mueller has another question: Why are we so worried about nuclear weapons in the first place? He's not so sure our hysteria over proliferation has any empirical support:

We have ... endured decades of hysteria over the potential for nuclear proliferation, even though the proliferation that has actually taken place has been both modest and substantially inconsequential. When the quintessential rogue state, communist China, obtained them in 1964 ... far from engaging in the "nuclear blackmail" expected at the time by almost everyone ... China built its weapons quietly and has never made a nuclear threat ... U.S. policy obsessed over the possibility that Saddam Hussein's pathetic and technologically dysfunctional regime in Iraq could in time obtain nuclear weapons (it took the more advanced Pakistan 28 years), which it might then suicidally lob, or threaten to lob, at somebody. To prevent this imagined and highly unlikely calamity, a war has been waged that has probably resulted in more deaths than were suffered at Hiroshima and Nagasaki combined.

Today, alarm is focused on the even more pathetic regime in North Korea, which has now tested devices that if detonated in the middle of New York's Central Park would be unable to destroy buildings on its periphery. There is even more hysteria about Iran, which has repeatedly insisted that it has no intention of developing the weapons. If that regime changes its mind or is lying, it is likely to find that, except for stoking the national ego for a while, the bombs are substantially valueless, a very considerable waste of money and effort, and "absolute" primarily in their irrelevance.

Is it true, as Mueller argues, contrary to a famous statement by Albert Einstein, that "[nuclear] weapons actually changed little except our way of thinking"?