Contrary to proper belief, it wasn't Yitzhak Rabin who called his old political rival, Shimon Peres, an “incessant underminer.” It was ghostwriter Dov Goldstein who coined the phrase for Rabin’s 1979 autobiography Service Book, and the former prime minister eagerlyappropriated it.

The label stuck for over three decades, during which Peres suffered the image of a shifty, unreliable meddler, which certainly contributedto his serial defeats (and one stalemate) in general elections, Labor party leadership votes (in over three decades of trying, he only won three) and the crowning humiliation of his loss to Moshe Katzav in the 2000 presidential contest.

Peres worked so hard for so many years to discard the meddler and loser brands associated with his name, and it seemed that he finally succeeded in 2007 on his second try to be elected president. This time he wasn’t going to allow anyone to accuse him of interfering and by and large he has remained aloof from political dispute, conducting himself in a regal manner, enjoying a nearly universal popularity that eluded him throughout half a century’s political career.

That is why I was so surprised when two and a half years ago, one of his aides said to me in a chance remark that “Shimon is doing everything to block Bibi and Barak’s crazy plan to attack Iran.”

It seemed to fly in the face of everything he had achieved since assuming the presidency. To clarify the aide’s remark, I asked one of Peres’ oldest confidantes, who told me “It’s true, Ashkenazi and the other security chiefs are all looking to Shimon to lead the opposition to a strike on Iran.”

IDF Chief of Staff Gabi Ashkenazi, Mossad Chief Meir Dagan and Shin Bet head Yuval Diskin are all since ex-chiefs and have revealed their personal opinions – Peres did so for the first time on Wednesday in his interview with Channel Two, in which he said:

"It's clear to us that we can't do it alone. We can only delay [Iran's progress]. Thus it's clear to us that we need to go together with America. There are questions of cooperation and of timetables, but as severe as the danger is, at least this time we're not alone."

For the first time, a rift has been opened publicly between the president and Prime Minister Benjamin Netanyahu, one which will not easily be closed - but it is only the first blatant sign of a tug-of-war which has been going almost since Netanyahu was elected three and a half years ago. The difference of opinions was hidden for most of this time, though it was clear enough in the way each of the leaders spoke about Iran in their speeches four months ago at the Holocaust Remembrance Day ceremony at Yad Vashem in Jerusalem.

We may never know the full story of how Peres has been trying to curb Netanyahu and Defense Minister Ehud Barak’s plans, but the president certainly laid the groundwork at an early stage.

Peres, of course, was never Netanyahu or Barak’s favored candidate for the presidency. He was elected thanks to previous PM Ehud Olmert’s efforts while Netanyahu, then leader of the opposition, fielded Knesset Speaker Reuven Rivlin and Barak pushed former diplomat and Labor MK Collette Avital for the job.

One of the first things Peres did upon entering the President’s residence was to bolster his ties with the security establishment. Not a week went by without a meeting between him and one of the heads of service, he was allowed to see the most classified information, things that no previous president had ever been privy to and the his office’s communications network was upgraded to allow the transmission of encrypted material.

Some of the documents were too sensitive to be sent and Peres became a regular visitor to the various headquarters in Tel Aviv, where he also met with key personnel and operatives. When the long-serving military attaché to the president, Brigadier-General Shimon Hefetz retired, he was replaced by Hason Hason, an intelligence officer and veteran of secret assignments, who was specifically tasked with keeping Peres abreast with privileged information.

At the time, Olmert was still prime minister and, not having a security background, he was happy for his ally Peres to be well-informed on national security matters. The president served in an unofficial capacity as the prime minister’s senior advisor and as a counter-balance to Barak, who had just returned to the defense ministry, having wrested the Labor leadership from Amir Peretz.

Barak was not yet powerful enough to challenge Olmert and at that stage, still had a cordial relationship with his subordinate Ashkenazi. Two years down the road, Netanyahu, forever suspicious of Peres, was prime minister and Barak was locked in intense rivalry with the IDF’s commander - but by then it was too late to break up the alliance between the president and Ashkenazi-Dagan-Diskin security triumvirate, none of whom had been appointed by the new political leadership.

Now they are on the outside, and their replacements - while not necessarily supporting a war on Iran - are of diminished stature. Peres, who turned 89 this week, is about to enter the last quarter of seven-year presidency. He has now finally emerged out in the open as the head of the anti-Iran war camp.

Why has he broken cover now?

There can only be two possible reasons. Either he believes that despite his and others’ efforts, Bibi and Barak are steadfast in their resolution and will imminently order the strike on Iran. Or, like other experienced observers, he does not believe they actually want to carry out the threat, but have maneuvered themselves into a position where to back down will also lead to considerable damage to Israel’s strategic standing.

Hence his efforts to couch his opposition in language about Israel’s strong alliance with the U.S. His appeal on Wednesday was directed towards Barack Obama just as much as it was to Netanyahu. He was essentially saying that there is only one ladder that will allow Israel’s leadership to climb down from escalation against Iran – a grand American gesture.