President Obama’s new Nuclear Posture Review has succeeded mightily in muddying the clear waters. He says we will not use nuclear weapons against a non-nuclear power. Except Iran. Except North Korea. If we are attacked with biological or chemical weapons, we will not retaliate with nuclear weapons. Is this a green light for another attack on the homeland? And what are the former captive nations of Europe supposed to think? Does any NATO member–like Poland, like Estonia–sleep more soundly with this ringing declaration of confusion, this uncertain trumpet?

When he was in Japan last fall, Mr. Obama pointedly avoided saying the U.S. use of nuclear weapons to end the carnage of World War II was justified. The American left–Barack Obama’s base–has been indicting Harry Truman for decades for dropping atomic bombs on Hiroshima and Nagasaki in August 1945.

Truman was facing the horrible prospect of losing 600,000 American lives in an invasion of the Japanese home islands. He also had to consider the real danger of millions Japanese civilian deaths in the combat and from mass suicides. The leftist Truman haters also never consider the 1,000 allied POWs dying weekly in Japanese captivity.

When Mr. Obama bowed low before Emperor Akihito, it was a tacit apology for all of that. Japan in 1945 was a non-nuclear power. The new Nuclear Posture Review is Obama’s elliptical way of saying Harry Truman was wrong.

Now we come to the mortal peril of Israel. Barack Obama is the most anti-Israel President in U.S. history. He has been willing to excoriate Benjamin Netanyahu’s shaky coalition government over Jews building apartments in East Jerusalem while cooing to despots in Riyadh and Cairo. Nobel Peace Prize Winner Elie Wiesel, a liberal supporter of Barack Obama, is in anguish. “Jerusalem is Jewish history,” he said in a full-page ad, an open letter to the President. “Jerusalem,” this Holocaust survivor said, “is the heart of our heart.”

Martin Peretz, of the New Republic, another liberal Obama backer, noted that Obama’s stiff-arming of Israel has served only to stiffen Palestinian intransigence. The PLO had “quickly surmised that Obama was in their corner and would not push them much. Their surmise turned out to be correct.” Former New York Mayor Ed Koch is distraught. He endorsed Barack Obama for President, but now cries: “I weep as I witness outrageous verbal attacks on Israel…that are being orchestrated by President Obama.”

Add to this dangerous mix, Mr. Obama’s cool and detached analysis of sanctions against an Iranian regime hell-bent on acquiring nuclear weapons. “Sometimes they work, sometimes they don’t.” Actually, most of the time, they don’t work. And they are especially doomed to fail when those who are supposed to be “crippled” and “bitten” by the “tough and smart” sanctions know there is no muscle behind the bluster. Even the Chairman of the Joint Chiefs of Staff–Mr. Obama’s top military man—knows his administration has no clue what to do about Iran.

Mahmoud Admadinejad, the mouthpiece for the Iranian mullahs, repeatedly says he envisions a world without Israel, a world without the U.S. And he responds to Obama’s neutering Nuclear Policy Review with withering scorn. He celebrates Iran’s unimpeded advance toward nuclear weaponry with open taunting of the toothless U.S. policy.

I believe Truman was justified in that hardest of all presidential decisions. Tens of millions of Americans and Japanese are alive today because Truman had the determination and grit to take that awful decision.

As justified as we were then, Israel would be even more justified in using tactical nuclear weapons now to eliminate the Iranian nuclear threat to the world. Japan in 1945 presented no existential threat to the U.S. Iran is just such a threat–to Israel, to NATO, and to us.

When the Israelis struck Saddam Hussein’s nuclear Osirak plant in 1981, the world howled. Even our U.S. State Department–under Alexander Haig–condemned the raid. The anti-Israel majority at the UN threatened sanctions against the Jewish state. President Reagan effectively sidetracked sanctions then.

But if Israel had not acted swiftly and effectively against Saddam Hussein then, the United States would not have been able to eject him from Kuwait a decade later with so little loss of American life. Saddam would have become the dominant power in the Mideast. That he did not rain nuclear missiles on Israel in 1991 is wholly attributable to the Israelis’ brave and skillful raid of 1981.

Mr. Obama’s feckless policies are giving the Israelis no choice. He wasted 15 months in fruitless overtures to the Iranian terror leaders. He advanced toward them with an open hand; they spit in his open hand. Bullying democratic Israel and coddling terror states is no policy.

April is the month when millions of Jews and their righteous Gentile friends around the world reflect on what it means to be a stateless, powerless, hunted people. Jews remember the Holocaust and say “Never Again.” Whether the United States under Barack Obama is with them or not, Israel has a right to act to make sure: Never Again.