WASHINGTON ― The rocket strikes that a militant Islamist group recently fired from the Egyptian Sinai into the Israeli city of Eilat served as yet another reminder of how delicate bilateral relations remain two years after Egypt’s revolution. Terrorist activity could easily cause a crisis on the border, with the potential to trigger an unwanted confrontation that would threaten the peace treaty that normalized bilateral relations in 1979. To avoid such an outcome, Israel and Egypt must take convincing action now to uphold the treaty.

Last November, when hostilities erupted in Gaza, Egyptian President Mohamed Morsi mediated a swift resolution, even providing a guarantee for the cease-fire with Gaza’s ruling Hamas. Morsi thus implicitly recommitted Egypt to upholding peace on the border and to playing a constructive role in the Palestinian-Israeli conflict. This boosted confidence in Israel that the Muslim Brotherhood, Egypt’s ruling party, would uphold the 1979 peace treaty. But Morsi has not explicitly endorsed peace with Israel and has avoided direct engagement with Israeli leaders.

Preserving peace is in both countries’ interests. The attack on an Egyptian army outpost in the Sinai last summer, in which armed militants killed 16 soldiers, demonstrated that terrorism threatens Egypt just as it does Israel.

In this volatile environment, reverting to a confrontational relationship with Israel would be extremely dangerous, inviting the risk of another disastrous war. Upholding the peace treaty with Israel would have the opposite effect, enabling Egypt to pursue its goals of consolidating the military’s authority at home and enhancing its influence throughout the Middle East.

Egyptian and Israeli leaders must recognize that the ongoing struggle to secure the Sinai Peninsula ― which the treaty established as a demilitarized zone ― is testing peace daily. Israel has so far tolerated Egyptian military activity and force deployments that technically violate the bilateral treaty, approving them retroactively in the hope that Egypt will do more to secure the border and crack down on weapons smuggling into Gaza. But Israel has little confidence that the deployments will enhance its security, and Israeli leaders are becoming increasingly anxious about the Egyptian military’s mobilization of forces without notice.

In Egypt, the treaty is even more clearly under threat. The Muslim Brotherhood has long called for a referendum on the treaty, viewing the restrictions on Egyptian forces in the Sinai as an affront to national sovereignty. The Brothers condemned Morsi’s involvement in resolving the Gaza crisis last year, portraying it as kowtowing to Israel.

In fact, Morsi is under fire from both the left and the right for upholding former President Hosni Mubarak’s obliging approach to Israel, as well as for reasserting Mubarak’s authoritarian bargain ― diplomatic and financial support in exchange for “stability” ― with the United States. Faced with a collapsing economy and approaching elections, the temptation for Morsi to stoke nationalist, anti-Israel sentiment will become stronger. A major incident on the border could be enough to push him over the edge.

In order to sustain the peace treaty, Egypt and Israel should renegotiate its military annex to allow Egypt to deploy forces in previously restricted zones and re-establish full sovereignty over the Sinai. Such a move would strengthen bilateral relations, generate goodwill in Egypt, and increase Israel’s confidence in the Muslim Brotherhood’s commitment to peace.

During such a renegotiation, the two countries would discuss in detail the most effective approach to tackling their shared challenges related to terrorism and transnational crime, in order to ensure that Egypt’s increased military presence in the Sinai also enhances Israel’s security. Egypt’s newly democratic government would be more strictly accountable for fulfilling the treaty’s terms if it played an active role in establishing them. At the same time, the agreement would boost domestic support for Egypt’s government and enhance its regional standing.

Likewise, U.S. involvement in the negotiations would benefit all parties. The process would provide an opportunity for the Egyptian military to engage with the U.S., helping to bolster its case for aid in a difficult environment.

Moreover, the U.S. could set clear, narrow terms for the talks and provide a guarantee that the outcome would not impinge on Israel’s core interests, thereby mitigating Israeli officials’ fears that opening the treaty’s military annex for revision would call into question its other terms. Finally, playing a successful role in bolstering Israel-Egypt relations could advance U.S. Secretary of State John Kerry’s diplomatic initiatives in the Middle East.

In a region as volatile as the Middle East, no country can afford to take peace for granted. But, by renewing their bilateral treaty now, Egypt and Israel would maximize their chances of prolonging an arrangement that has kept them from fighting for more than three decades.

By Itamar Rabinovich and Tamara Wittes

Itamar Rabinovich, a former ambassador of Israel to the United States (1993-1996), currently is based at Tel Aviv University, New York University, and the Brookings Institution. Tamara Wittes is director of the Saban Center at the Brookings Institution. ― Ed.

(Project Syndicate)