A major controversy erupted last week when Israel announced that Egyptian President Mohammad Morsy had sent a letter in reply to Ramadan greetings he had received from Israeli President Shimon Peres. Spokespersons for Morsy's office, his Freedom and Justice Party, and the Muslim Brotherhood issued angry denials, calling the reports “fabrications” and “lies” spread by the Israeli media in order to embarrass Egypt’s new Islamist president.

The facts are still somewhat murky, but following the denials, first the cover sheet of the fax from the Egyptian Embassy in Tel Aviv was released to the Israeli media, and then an image of the purported letter itself was posted on Peres’ Facebook page. The letter includes this pledge: “I am looking forward to exerting our best efforts to get the Middle East Peace Process back to its right track in order to achieve security and stability for all peoples of the region, including the Israeli people.”

The letter and cover sheet appear genuine. Some have argued that the misspelling of Peres’ name as “Perez” indicates a forgery, but it seems at least as likely, if not more so, a bureaucratic error than an indication of a crude fake. At this stage it is almost certain that this letter was actually faxed by the Egyptians. Because the language is boilerplate, reflecting traditional Egyptian communications with Israeli officials, it’s remotely possible that its content was shaped by Egyptian diplomats without the detailed approval of the president’s office in Cairo. Very probably, though, the letter, which does not bear Morsy’s signature, is indeed a genuine communication between the two presidents. Assuming that’s the case, what explains the letter, its contents and denials on the Egyptian side regarding its authenticity?

First, the letter suggests that, as one would have anticipated, Egypt’s actual foreign policy hasn’t changed under the new president, because its interests haven’t changed. Morsy has to deal with the same equation that other Egyptian leaders have faced, and cannot abandon decades of foreign policy because of a different ideological orientation.

Last Sunday's attack on Egyptian forces in the Sinai Peninsula by masked gunmen demonstrates this dynamic precisely. There's no question that the assailants are pursuing an agenda that undermines both Israeli and Egyptian interests simultaneously, forcing the two sides to re-examine contentious positions. Egypt can no longer dismiss Israel's often-stated concerns about security in Sinai, because its own interests have been directly attacked. Meanwhile, Israel cannot expect Egypt to deliver on security while maintaining a de facto demilitarized zone in the north of the Peninsula, according to the terms of the now decades-old peace agreement. These are the dangerous international waters the Egyptian state, including its new president, must navigate.

Moreover, Egyptian Muslim Brotherhood officials have been working hard to convince the United States not to be alarmed by the party’s rise to power in Egypt, particularly regarding the peace treaty with Israel. So the motivations for such a letter from the point of view of Egypt’s national interests, and even the interests of the Muslim Brotherhood, are not particularly mysterious.

It’s also likely that Morsy and his allies, assuming they did approve the communication, were surprised that the Israeli government would “embarrass” them with their own supporters by announcing its receipt and, worse still, by revealing its contents.

Second, if genuine, the letter confirms a truism that may apply to most governments around the world to some extent, but has been particularly evident in the Middle East, where governments often conduct foreign policies that are inconsistent with their public statements and their ideological slogans.

Morsy’s predecessor Hosni Mubarak, for example, proved unable to explain Egypt’s policies to the public during the 2007-2008 Gaza war because of precisely such a disconnect between Egypt’s actual interests and its foreign policy pronouncements. Syrian President Bashar al-Assad’s claim to be the champion of the Palestinian cause has been thoroughly exposed for the lie it has always been. This applies to many other states in the region as well.

The Palestinians themselves have experienced the price of this disconnect between politics and policy on numerous occasions. One obvious example was their mishandling of the Goldstone Report on the Gaza war, during which they could not successfully reconcile statements aimed at domestic public consumption and imperative diplomatic considerations.

As for Israel, anyone who still takes at face value Prime Minister Benjamin Netanyahu’s professed commitment to a genuine two-state solution is simply being naïve given his governments policies, especially regarding settlement expansion.

Finally, anyone, whether on the Arab or Israeli side, who thought that Egypt’s Islamists were necessarily going to eagerly move their country into a more hostile relationship with Israel was deluded. Even sillier was the notion that Islamist politicians would be more honest and straightforward with the public than nationalist ones.

Even Hamas is drawing back on its rhetoric that placed so much hope in Islamist rule in Cairo. Recently, it had to send a delegation asking Egypt to open the crossing point with Gaza, which, in spite of numerous announcements, it has yet to do.

When they operate in opposition, ideologically extreme parties benefit from harsh rhetoric on foreign policy designed to draw contrasts with existing governments. But when they come to power, they quickly find themselves responsible for the national interest and facing the very same set of intractable problems and limited options their predecessors did.