WASHINGTON ― As Prime Minister Benjamin Netanyahu continues his almost daily demands that the U.S. announce its “red line” for going to war with Iran, the question puzzling the White House is what the Israeli leader wants beyond what President Obama has already stated. 

Obama believes he has drawn the U.S. red line as clearly as a superpower ever should, given that some ambiguity is useful in deterring an adversary. For the record, Obama said in an interview with Jeffrey Goldberg of The Atlantic last March that it was “a profound national security interest of the United States to prevent Iran from getting a nuclear weapon.” U.S. intelligence would provide “a pretty long lead time in which we will know that they are making that attempt.”

Obama was even more explicit in a speech a few days later to the American Israel Public Affairs Committee: “I have a policy to prevent Iran from obtaining a nuclear weapon.”

Beyond this rhetorical pledge, Obama has directed the U.S. military to prepare detailed plans for attacking Iran if it should cross the line he has set. The Israelis know what signals the U.S. will look for in determining if Iran has begun weaponization, and what weapons the U.S. will use in its preventive attack.

So what is it that Netanyahu seeks from Obama that he hasn’t yet gotten? Apparently, it’s some sort of ultimatum or deadline for Iran to stop its nuclear enrichment, which could someday provide fuel for a bomb. In the latest eruption, Netanyahu said Tuesday that leaders who won’t make such ultimatums “don’t have a moral right to place a red light before Israel.”

The White House might reasonably respond by asking: What are Israel’s “red lines”? If it doesn’t accept the president’s public commitment to stop Iran, then where would it draw the line? It has been hard to get a clear answer.

Israel says Iran shouldn’t have nuclear enrichment capability, but unfortunately that line was crossed long ago. Now, apparently, Netanyahu wants to prevent the Iranians from installing enough centrifuges in their fortified mountain base near Qom that they would enter a “zone of immunity,” in which they could produce enough highly enriched fuel for a bomb. But how many centrifuges are we talking about? And if the U.S. can bomb Qom and destroy the centrifuges, why does this issue matter so much?

Watching Netanyahu’s public, Hamlet-like anguishing over the past year about “to bomb or not to bomb,” one suspects the real issue for him isn’t red lines so much as trust that they will be enforced. Despite Obama’s record of lethal covert action against al-Qaida, he clearly hasn’t convinced Bibi.

Netanyahu should understand that no country can allow another to impose the conditions under which it will go to war. The Israeli leader wants a tripwire that would trigger military action. But presidents don’t turn over that power of war and peace, even to their best friends. Indeed, it’s precisely because Obama means what he says about going to war that he wants maximum flexibility in how and when he takes action.

The Israeli leader also ought to realize by now that Obama doesn’t like to be jammed. That’s the most interesting revelation of Bob Woodward’s new book, “The Price of Politics.” The book describes how Obama was prepared to risk a financial default last year in preference to giving congressional Republicans a chance to create another debt-ceiling crisis during the 2012 election year. “He could not give the Republicans that kind of leverage. ... It was blackmail,” explains Woodward.

In the White House view, Netanyahu is trying to do the same thing that House Speaker John Boehner attempted, and this isn’t likely to work. And officials are surely peeved that Netanyahu is making such comments (and pushing for a personal meeting) in the middle of the U.S. election campaign.

The danger of these months of semi-public Israeli debate about going to war is that rather than making Tehran tremble, they may lead Iranian leaders to doubt Israeli resolve. Netanyahu is creating a situation where he almost has to attack, to save face. Obama should help the Israeli leader to climb down from his unwise rhetoric.

Yes, the U.S has already drawn a red line. But it’s worth restating, publicly, perhaps in a very visible forum such as the U.N. General Assembly later this month. The U.S. needs to take control of the deadly confrontation with Iran, rather than being cajoled and buffeted by its smaller, weaker ally. Obama needs to own the policy of prevention he has declared. 

By David Ignatius

David Ignatius’ email address is davidignatius@washpost.com.

(Washington Post Writers Group)