The fifth Cypriot-Greek-Israeli summit will take place in Beersheba on December 20. While much of Israel’s attention is focused on Iran’s proxies on the country’s northern and southern borders, this high-level trilateral meeting is a noteworthy strategic event.Hezbollah in Lebanon, Iranian militias in Syria, and Hamas in Gaza are serious military challenges along Israel’s northern and southern borders. They contribute to a new emerging threat in the eastern Mediterranean. Each of these bad actors is under Iranian influence.Iran, which is seeking a Shi’ite corridor from the Persian Gulf to the Mediterranean, plans its own air and naval bases on the Mediterranean coast, too. This would allow Iran to project power into the Balkans along the Mediterranean shores, and further west, too, toward the Muslim communities in Europe. There are three Muslim states in the Balkans (Albania, Bosnia and Kosovo) that have already been penetrated by Muslim powers Turkey and Iran.Turkey has adopted a neo-Ottoman foreign policy orientation and signaled its desire for expansion. It is a strong state with a long Mediterranean coast. Turkey’s military has invaded parts of Syria and Iraq, and it has had a long territorial dispute with Greece in the Aegean. Since 1974, Turkey has occupied the northern part of Cyprus, a strategic location in the eastern Mediterranean.Turkey’s behavior is also motivated by Islamist instincts. It has supported the radical Islamic Hamas government in Gaza and nourished good relations with jihadist elements in Syria and Libya – both Mediterranean countries. Turkey is bolstering its naval capabilities, and has even threatened to send its navy to accompany ships that attempt to break the Israeli naval blockade around Gaza. Ankara’s Islamist preferences clearly put it at loggerheads with Jerusalem.Unfortunately, the Mediterranean is no longer a Western lake. Over the Obama years, the US significantly retreated from the Middle East. President Donald Trump has also displayed isolationist sentiments, despite a commitment to enhance US military power. A weakened American military posture is reflected in that the US Sixth Fleet no longer has a permanent aircraft carrier presence in the Mediterranean. (This is also true of the Seventh Fleet in the Indian Ocean.) European naval fleets have similarly lost some of their capabilities and reduced their presence in the eastern Mediterranean.Instead, the Russian eastern Mediterranean naval presence is growing. Russia secured for itself the naval base at Tarsus and the air base at Khmeimim in Syria, by intervening successfully in the Syrian civil war. Cyprus and Egypt also allow Russia use of their ports. The importance of the eastern Mediterranean in international affairs has grown due to the discovery of large underwater natural gas fields, with more likely to be yet discovered. These gas riches are coveted by Iran’s allies (Syria and Hezbollah) as well as by Turkey and Russia.The eastern Mediterranean has always been important to Israel because over 90% of Israel’s foreign trade traverses this area. The gas fields discovered and now being mined in Israel’s Mediterranean economic waters have magnified the importance of the Mediterranean arena. The gas is expected to make a significant contribution to the well-being of Israel by providing cheap and clean energy, and by transforming Israel into an energy exporting country.However, Israel’s gas riches are under threat. Hamas and Hezbollah are investing in their naval forces. Hamas already has fired missiles against an Israeli-operated gas rig, and Hezbollah has threatened to do so. Russian and Turkish navies might yet adopt more adventurous postures, too. There may soon be an Iranian naval presence commensurate with Tehran’s hegemonic ambitions.Thus, Israel has one more strategic flank to protect. Unfortunately, the naval component in the Israeli military has not been sufficiently prioritized. Israel needs a bigger and stronger navy. The rationale for a larger Israeli naval force is even more compelling given the enormous missile threat aimed at Israel, making Israel’s airfields and strategic ground assets ever more vulnerable.Israel’s military deficit in the eastern Mediterranean is striking, in light of its diplomatic success. It became a close partner in an eastern Mediterranean alignment that consists of Greece and Cyprus. Egypt is indirectly also a member, although it prefers to interact separately with Israel. The four countries share similar concerns about Turkish foreign policy directions and have similar energy interests. Cooperation in Washington on eastern Mediterranean issues is also important; indeed, the US is mulling the option of joint military exercises with Israel and Greece.The writer is president of the Jerusalem Institute for Strategic Studies and a fellow at the Middle East Forum.