'We may no longer live in fear of global annihilation," President Obama declared on Wednesday, "but so long as nuclear weapons exist, we are not truly safe." He's right about the last point, because even as the President offers new dreams of U.S. nuclear disarmament, the world is entering a new proliferation age.

Mr. Obama returned this week to Berlin to give his long-promised speech laying out his plans to rid the world of nuclear weapons. His idea is to remove those weapons initially and primarily from American hands. North Korea and Iran each got a single line in his speech, which is at least more than he gave to China, which is investing heavily in the world's third largest nuclear arsenal. Nukes in the hands of terrorists? Mr. Obama said he'll hold a summit on that one in 2016.

Give Mr. Obama points for consistency. Since his college days at Columbia in the 1980s, he has argued for American disarmament and arms-control treaties. When he last issued a call for a nuclear-free world on European soil four years ago in Prague, the Norwegian Nobel Committee rewarded him with a peace prize.

This week he announced that the U.S. could "maintain a strong and credible strategic deterrent" with a third fewer strategic nuclear weapons, or about 1,000 in all. He also called for "bold" cuts in tactical nukes in Europe without offering specifics, which suggests that was mostly for show.

He said he'll work on reducing U.S. stockpiles through "negotiated cuts" with Russia. Whenever this Administration negotiates with Russia, beware. But there's another danger. President Obama left the door open to unilateral U.S. reductions, possibly without Congressional approval.

The Berlin initiative is the long-promised follow-up to the 2010 New Start accord with Russia, which brought down stockpiles of warheads, missiles and bombers. In his speech this week, President Obama urged everyone to "move beyond Cold War nuclear postures." But is there anything that evokes the Cold War more than arms control with Moscow?

Even the Kremlin isn't likely to embrace this new offer. "We cannot endlessly negotiate with the United States the reduction and limitation of nuclear arms while some other countries are strengthening their nuclear and missile capabilities," Deputy Foreign Minister Sergei Ryabkov told Russian radio last month. By "some others," he means China.

Good point. Bilateral negotiations are an anachronism. Before the Cold War powers cut any deeper, how about some clarity about the size of the Chinese arsenal and its intentions? Beijing hides its warheads and missiles in tunnels and has the industrial wherewithal to build many more quickly. The Pentagon thinks the Chinese have up to 400 nuclear warheads, which sounds low. The Pakistanis possess more than 100.

The Russians are terrified of a rising Chinese military on their long southern border. Beijing likely has 1,800 bombs and warheads, the former commander of Russia's Strategic Forces told the military journalist Bill Gertz last year. Whether this number is accurate or not, the Russians think it is. They're reluctant to give away any more of their rusting strategic long-range arsenal. Forget about any progress on thinning Russia's formidable stockpile (size unknown) of shorter-range tactical weapons.

Yet engaging in arms talks could give the Kremlin fresh leverage over America's missiles defenses. The Russians have wanted to kill the program since Ronald Reagan made it a priority, and they have found a weakness in President Obama's dreams of disarmament. To get New Start, the White House in 2009 cancelled plans for a missile defense site in Poland that would protect the U.S. against an Iranian ICBM.

Mr. Obama is literally pleading with Moscow to strike another arms deal, which underscores the surreal nature of his vision. He handed the Kremlin reams of classified data about American missile defense, supposedly to allay fears that U.S. defenses will weaken Russia's nuclear deterrent. Invoking executive powers, the Pentagon and State Department rebuffed requests by Congress to specify the information shared with Russia to see if it might have jeopardized U.S. security.

Even if Russia won't go along, Mr. Obama's new nuclear strategy says the U.S. has more warheads, missiles and submarines than it needs. The White House can invoke this conclusion to prune the arsenal through budget cuts or executive orders. This way he can also impose changes to America's missile defenses sought by the Russians without direct Congressional approval.

Meanwhile in the real world, North Korea adds to its nuclear arsenal and tests weapons with impunity. Iran marches ahead toward its atomic capability despite U.N. sanctions. Their neighbors in Asia and the Middle East watch and get ready to build or buy their own weapons in response. The legacy of the President who dreams of nuclear disarmament is likely to be a world with far more weapons and more nuclear powers.