If anyone still harbored illusions that power would moderate the Muslim Brotherhood, Sunday’s attack in Sinai should have shattered it. Heavily armed jihadis stormed an Egyptian army outpost, slaughtered 16 Egyptian solders, stole two APCs and raced toward the Israeli border, where the Israeli army finally stopped them. As Jonathan optimistically wrote yesterday, this is one crime “that cannot be blamed on Israel.”

Except, of course, the Muslim Brotherhood proceeded to do exactly that: As the Jerusalem Post reported, “Egypt’s Muslim Brotherhood said on its website that the attack ‘can be attributed to Mossad’ and was an attempt to thwart” Egyptian President Mohammed Morsi, the Brotherhood’s man in Cairo.

According to the Brotherhood statement, the Mossad “has been seeking to abort the revolution since its inception and the proof of this is that it gave instructions to its Zionist citizens in Sinai to depart immediately a few days ago.” The group added: “(It) also draws our attention to the fact that our forces in Sinai are not enough to protect it and our borders, which makes it imperative to review clauses in the signed agreement between us and the Zionist entity.”

But it gets even worse. Israel had advance intelligence of the attack – hence its warning that Israelis should leave Sinai, and the heightened alert along the border that enabled it to stop the terrorists with no Israeli casualties. And like a good neighbor, it shared some of this intelligence with the Egyptian army.

Egypt, however, evidently ignored the information: There’s no sign that it beefed up security along the border or placed its soldiers on heightened alert.

In short, the new Egypt is so unwilling to cooperate with Israel that it wouldn’t even act on Israeli intelligence about a threat to its own security. And given the Brotherhood’s subsequent statement, one can see why: It doubtless viewed the warning as a devious Mossad plot aimed at weakening Egypt in some unknown fashion.

All this confirms the impression left by last week’s fiasco, when Morsi replied to Israeli President Shimon Peres’s Ramadan greeting. The reply was faxed from the Egyptian embassy in Tel Aviv with a cover note on embassy letterhead. But when the eternally optimistic Peres publicized it, deeming it a “hopeful” sign, both Morsi’s spokesman and his top aide flatly denied that any letter was ever sent. His spokesman even termed the media reports a “slander.”

In short, Morsi is willing to throw occasional bones like the Peres letter, so that Western countries whose money he needs to rescue Egypt’s economy can keep deluding themselves of his moderation. But back home, where it counts, accusing him of any contact with Israel – even something as banal as acknowledging a Ramadan greeting – constitutes “slander.”

There’s a clear lesson for Israel in all this: If, as expected, Egypt seeks to bring more troops into Sinai (which requires Israel’s permission under the peace treaty), Jerusalem should say no. Because given the Morsi government’s attitude to date, those troops won’t cooperate with Israel; they’ll at best stand idly by whenever the jihadis attack Israeli targets, and at worst may target Israel themselves.

Israel already has enough problems in Sinai; it doesn’t need even more Egyptian troops standing around and doing nothing to solve them. That just means more soldiers who could get caught in the cross-fire – thereby increasing the risk of an Israeli-Egyptian war.