The Obama administration is nervously monitoring the apparently deteriorating relationship between Israel and Egypt in the wake of last week's storming of the Israeli embassy in Cairo by angry protesters. Israeli Prime Minister Benjamin Netanyahu has promised to intensify efforts to erect a metal fence on the Israeli-Egyptian border. Why the sudden outburst of anger against Israel? Here, four theories:

1. Egypt's military regime is using Israel as a scapegoat

The leaders of the popular revolution that drove out longtime ruler Hosni Mubarak are growing frustrated with the military regime that replaced him, says The Washington Post in an editorial. Those in control are trying to "divert rising public unrest toward a familiar target": Israel. The military is even using the embassy attack "as a pretext to apply emergency laws and censor the media." But the generals are dreaming if they think "scapegoating Israel" will satsify the Arab Spring masses demanding change.

2. The anger was always there — but Egyptians couldn't express it

"Israel's dilemma is that the Middle East, for all the talk of revolution, is slipping backward," says Richard Cohen, also in The Washington Post. The country lived for decades under a peace deal imposed by Anwar Sadat, but now it's unraveling. "The peace with Israel has little support among the populace. It's not just that Israel is not loved, it's that Jews are hated." And the Egyptian government no longer has the power to tell its people to keep their hatred in check.

3. Netanyahu is stirring up Israel's enemies

Egyptians "identify Netanyahu with the Mubarak regime," says M.J. Rosenberg at Al Jazeera, which only feebly protested "against the occupation of the West Bank or the strangulation of Gaza." After Mubarak fell, Netanyahu made matters worse by refusing to apologize to Turkey for killing its nationals at sea as they tried to run the Gaza blockade. He also ended negotiations with the Palestinians by refusing President Obama's request for a settlement freeze. "It is Netanyahu who, more than anyone else, is responsible for the tsunami heading Israel's way."

4. The Arab Spring rekindled Egyptians' national pride

The explosion of anger against Israel has nothing to do with Egyptians' support for the Palestinian cause, says Eric Trager at The New Republic. Despite the enduring Camp David Accords, "Egyptian national pride remains tied to the country’s previous wars with the Jewish state. It's therefore all too predictable that the groundswell in Egyptian nationalism that ousted Hosni Mubarak this spring has been accompanied by an equally powerful surge in anti-Israeli sentiment."