The Web site World Net Daily does a remarkably thorough job in reporting (and often encouraging) the most aggressive rumors circulating in conservative media. So it naturally ran a story on Sunday complete with a sweet graphic of diving jet fighters, based on a rumor: "Report: Obama threatened to shoot down Israeli Jets." When even WND adds the rump-covering "Report:" to a headline, you know you ought to be suspicious.

The story, details of which we'll get to in a moment, is not true. The conservative Washington Times asked the White House for a response, and the administration's answer was pat: "That report is totally false."

But that didn't keep it from being written up on a slew of Web sites and shared by conservatives on social media. "Did Obama threaten to shoot down Israeli planes if they attacked Iran?" HotAir's Jazz Shaw asked in his headline, making obvious the reason that the story was so resonant in the first line of the piece. "Reports came out overnight about a story which, if true, will be another damaging blow to the US – Israeli relationship," Shaw wrote. At a moment in which the relationship between the United States and Israel is heavily overlaid with partisan politics, the rumor about military hostility between the two raised some eyebrows.

It is, game-show-host-turned-conservative-firebrand Chuck Woolery -- or it would be if true. Woolery's tweet points to an article at the site of Arutz Sheva, which itself points to a report from the Ma'an News Agency, which points back to a report from a Kuwaiti newspaper called al-Jarida.

That last article is in Arabic, but the key quote comes in the last paragraph. In short, the claim is that an Israeli source told al-Jarida that Obama halted an airstrike by Israel against targets in Iran by threatening to shoot down the Israeli bombers. A Post staffer who reads Arabic translated the quote for The Fix as follows:

"Israeli fighter jets and drones entered Israeli airspace more than once taking off from secret bases in different countries, where they were able to penetrate Iranian radar. The goals were drawn and the plan is ready. However, one of the Israeli ministers was closely linked to the American administration and in that period, divulged the secret to secretary John Kerry, prompting Obama to contact Netanyahu, threatening to bring down Israeli planes before their arrival in Iranian airspace."

That's the claim, picked up by NewsMax and the Daily Mail and the Daily Caller.

A single-source anonymous quote detailing extremely high-level communication between the U.S. president and Netanyahu -- from a newspaper in a country that has no diplomatic relations with Israel.

There's political value, though, in stressing tension between Obama and Netanyahu. The latter's speech on Tuesday has become a flashpoint of partisan politics, and it will be boycotted by a number of Democratic members of Congress. And with the 2016 elections increasingly filling our windshields, the relationship between a critical American ally and a Democratic administration -- and its former secretary of state -- becomes only more significant.

Again, it's not true, as the White House itself tweeted on Sunday.

But the thought that it might be proved too tempting to ignore, however shaky the source.