Israel’s long-standing diplomatic goal of obtaining defensible borders in any future peace settlement has become even more compelling in recent years. Historically, since the 1967 Six-Day War, Israeli governments have insisted that the Israel Defense Forces (IDF) would not withdraw to the pre-war lines with the West Bank, from which Israel was attacked. In any case, these were formally only armistice lines from 1949, designating where the armies stopped in Israel’s War of Independence, so that any new international political boundary, it was felt, still needed to be negotiated.

Moreover, according to the carefully drafted language of UN Security Council Resolution 242, which was adopted five months after the Six-Day War, Israel was not expected to fully pull out from all the territories it captured. Basing themselves on Israel’s legal rights, the architects of Israeli national security doctrine, from Yigal Allon and Moshe Dayan to Yitzhak Rabin and Ariel Sharon, insisted that Israel needed defensible borders in the West Bank to protect itself against the plethora of threats it faced in the Middle East.

Pulling back to the 1967 lines would strip Israel of the territorial defenses that have provided for its security for nearly fifty years. It would be only nine miles wide at one point and without its formidable eastern barrier in the Jordan Valley, which to this day is viewed by Israel’s security establishment as the front line for its defense in the east.

This traditional Israeli position has acquired new salience against the background of three important recent developments:

Israel’s 2005 disengagement from the Gaza Strip that resulted in an enormous military buildup on the part of Hamas and other Islamist groups that benefited from the ability to fully exploit the Sinai-Gaza boundary area through which they smuggled far larger quantities of rockets and other weaponry.

What was initially called the Arab Spring–later labeled the Islamist Winter–erased much of the certainty that once existed about the stability of surrounding Arab regimes. The Arab-Israeli peace process had been predicated upon Israel assuming risks by its withdrawal from territories it captured in the 1967 Six-Day War, while being able to rely on neighboring regimes to assume responsibility for security in any area that Israel vacated.

The U.S. and its European allies have increasingly made known their view that another effort to resolve the Israeli-Palestinian conflict should be attempted, in which the territorial dimension be addressed up front. This has placed pressure on Israel to accept the notion of a withdrawal based on the 1967 lines.

The Impact of Gaza Disengagement

Israel’s decision to unilaterally withdraw from the Gaza Strip in September 2005 resulted in far-reaching military developments that have come to serve as a warning of what could happen in the West Bank if appropriate security arrangements and defensible borders are not in place.

Israeli planners might have expected that the rate of Palestinian rocket fire from the Gaza Strip would diminish after Israel’s withdrawal. After all, by pulling out its civilian settlement presence as well as its army positions, Israel was removing one of the principal grievances raised by Palestinian spokesmen.

There had been a steady escalation of Palestinian rocket attacks on Israeli targets since 2001, when four short-range Kassam rockets were fired on Israel. This number increased to 179 attacks in 2005–the year of the disengagement. But in 2006, in the aftermath of Israel’s withdrawal, the number of rocket attacks did not go down, but actually went up dramatically: there were 946 rockets launched at Israel, amounting to a more than 500 percent increase in the rate of rocket fire.

Another dimension of the post-Gaza withdrawal environment was the qualitative improvement of Palestinian rockets, especially with respect to range. Prior to 2005, Palestinian organizations were using the domestically-produced Kassam rocket that had a range of only seven kilometers. But in the aftermath of the Israeli withdrawal, the Palestinians began attacking a much wider belt around Gaza, striking the city of Ashkelon for the first time on March 28, 2006. During November 14-21, 2012, Palestinians fired 1,506 rockets at Israel, nearly reaching Tel Aviv and Jerusalem.

Newly imported rockets were entering the arsenals of Hamas and other organizations, including the 120 mm Grad rocket, supplied by Iran, with a range of 20-40 kilometers. Eventually, the Iranians exported the Fajr-5 rocket (range 75 kilometers) to Hamas. Russian armor-piercing missiles like the “Konkurs” also entered the Hamas arsenal. In 2011, Hamas fired a Russian-manufactured “Kornet,” an advanced laser-guided, anti-tank missile, at a yellow Israeli school bus in southern Israel, killing a 16-year-old boy.

Finally, shoulder-fired anti-aircraft missiles like the SA-7 “Strella” appeared, which had to be taken into account by Israeli pilots flying within Israeli airspace adjacent to Gaza. A new wave of shoulder-fired missiles came into Gaza through the smuggling tunnels in 2011 from Libya, after the overthrow of Muammar Kaddafi. In the meantime, Hamas operatives also exited the Gaza Strip though the tunnel system, reaching Egypt and then flying to Syria and on to Iran for advanced military training.

The key to understanding these developments in the weaponry deployed by Hamas and other organizations is to look at what happened on the outer perimeter of the Gaza Strip along its border with Egyptian Sinai. The original 1994 Gaza-Jericho Agreement between Israel and the PLO was the first implementation agreement under the Oslo Accords, creating a very narrow strip along the border area that continued to be under Israeli military control. It was formally designated on the maps as the “Military Installation Area,” but was code-named by the IDF as the “Philadelphi Route.”

When Palestinian organizations began to dig smuggling tunnels underneath the Philadelphi Route, the IDF waged a difficult counter-insurgency campaign to identify the location of the tunnels and eliminate them. After the Gaza disengagement in 2005, Israel was no longer able to send in forces to try to close down the tunnels, so their numbers mushroomed. Hundreds of smuggling tunnels were opened and the amount of weaponry reaching Gaza increased accordingly. Without close Israeli control, Hamas developed a domestic production capability for longer-range rockets as well.

As a result, Israel was forced to conduct repeated military campaigns Operation Cast Lead (December 27, 2008-January 18, 2009), Operation Pillar of Defense (November 14-21, 2012), and Operation Protective Edge (July 8-August 26, 2014) to suppress Hamas rocket fire.

In contrast, when Israel conducted Operation Defensive Shield (March 29-May 3, 2002) in the West Bank to halt a wave of suicide bombing attacks on its cities, it was able to seal off the territory from any external reinforcement, leading to a far more decisive result than in the case of Gaza. Shoulder-fired anti-aircraft missiles may have entered the Gaza Strip, but no such weaponry reached the West Bank, where the strategic consequences of their arrival would be enormous, given the proximity of Ben-Gurion International Airport to the pre-1967 line.

Jordan has acted to prevent smuggling into Israel or the West Bank from its territory, but it, too, faces a growing challenge, which it has openly admitted. In December 2013, the commander of the Jordanian Border Guard, Brig.-Gen. Hussein Zayoud, disclosed that smuggling over the Syrian-Jordanian border had more than tripled during 2013. At some point, when the situation within Syria stabilizes, this smuggling industry could be re-directed westward and involve itself in the Israeli-Palestinian conflict. Thus, Israeli concerns with the Egyptian scenario replicating itself along the Jordan-West Bank border are no exaggeration.

The lesson for Israel in planning West Bank security was clear. The equivalent of the Philadelphi Route in the West Bank is the Jordan Valley. Beyond the utility of the Jordan Valley as a strategic barrier in the event that Israel is drawn into conventional warfare, the area has acquired new importance in Israel’s public debate, since no one wants to replicate the errors of the Gaza disengagement on a much greater scale in the West Bank. Continuing to seal the West Bank from external reinforcement remains critical and Israel can only trust its own forces–rather than international troops–to carry out that task.

An additional lesson from Gaza disengagement had to do with how costly it would be for Israel to try to correct any errors from a poorly executed withdrawal. In 1993, presenting the Oslo Accords to his Labor Party faction in the Knesset, Prime Minister Yitzhak Rabin remarked that if it all goes wrong, “there is always the IDF.” An underlying assumption from the unilateral Israeli withdrawal from Lebanon in 2000 was that, having pulled out, Israel would have far more international legitimacy if it was required to use force in the future. Undoubtedly, a similar calculus existed with the Gaza disengagement five years later.

But when this thesis was tested, it turned out to be terribly wrong. Even though Israeli civilian population centers had been repeatedly struck by escalating Hamas rocket attacks, the moment Israel forces re-invaded large parts of the Gaza Strip during Operation Cast Lead, it faced severe international condemnation, including a well-publicized investigation of its military actions by the UN Human Right Council, which came to be known as the Goldstone Report.

As a result, while Israel possesses the military power to re-invade territory from which it has withdrawn, the political price makes reliance on this option largely prohibitive. What makes more sense is to make sure Israel has defensible borders, through which it can prevent any territory it evacuates from turning into a base for attacking the people of Israel.

The Arab Spring and the Fragmentation of the Arab State System

One underlying assumption of the Arab-Israeli peace process since 1967 has been that if Israel withdraws from territory captured in the Six-Day War, there will be a responsible Arab government on the other side to assure the security of the vacated area. Even in the separate case of southern Lebanon, which saw IDF ground action in 1978 for the first time, UN Resolution 425, which Israel came to support, specifically called for the restoration of the authority of the Lebanese government as part of any future Israeli withdrawal.

However, the Arab Spring beginning in 2011 presented new factors in the Arab world that will have to become part of Israel’s future calculus if it contemplates withdrawal from any part of the West Bank. First, the central governments of many Arab states have been badly weakened, if not entirely replaced, and are in no position to exert control over large parts of their sovereign territory. In Libya, the central government in Tripoli lost control over the western part of the Libyan state, known as Cyrenaica. In Egypt, the Sinai Peninsula increasingly appeared to be beyond the control of the government in Cairo. By 2013, large parts of Syria were no longer governed by Damascus. Notably, Jordan remained an island of stability amidst regional turmoil. Perhaps its internal situation has been strengthened by what is transpiring around it; after all, who in Jordan would want to import the bloodbath of Syria or Egypt into the kingdom?

There were those who greeted the disintegration of Arab states as a security windfall for Israel. True, with the collapse of the Arab states, it would become extremely difficult for them to maintain the kinds of large force structures that were so prevalent for much of the Cold War. Israel originally conceived of defensible borders as a strategy that would allow its relatively small standing army to withstand and contain quantitatively superior Arab armies until the IDF completed its reserve mobilization and reached full strength. That scenario appears less relevant in a Middle East enmeshed in internal revolts, leading some to suggest that Israel was facing a more benign strategic environment.

That conclusion is mistaken.

Long-term planning cannot be based on a snapshot of reality in a given year, but has to take into account different possible ways the military balance in the Middle East can evolve over time.

Israel will be operating in the years ahead with a large degree of uncertainty. As a result, long-term planning has to take into account different ways the military balance in the Middle East can evolve over time. Unquestionably, some Arab states will inevitably rearm after they become more stable. Iraq has already begun the long road to rebuilding its ground forces with the acquisition of U.S. M1A1 Abrams tanks, as well as older Soviet military hardware like the T-72 main battle tank with which the Iraqis are more familiar. Armor remains a significant component of military power for many Middle Eastern states.

In the near term, the conventional military threat is being superseded by a new global jihadist challenge. Across the region, the vacuum is being filled by al-Qaeda-associated and independent movements that do not recognize the international borders of the Middle East state system. In July 2013, the head of IDF military intelligence, Maj.-Gen. Aviv Kochavi, warned that in the “immediate future” the dangers to Israel were increasing. He focused on the al-Qaeda presence in Syria:

Syria is the most disturbing example, drawing thousands of global jihad activists and radical Islamists from the region and beyond. They are establishing themselves in Syria, not only to oust Assad, but to promote their vision of a Sharia state. In plain sight, on our doorstep, a global jihad stronghold of great magnitude is being established. This reality could potentially affect not only Syria and the border with Israel but Lebanon, Jordan, Sinai and the entire region as well.

The head of IDF operations, Maj.-Gen. Yoav Har-Even, noted in early 2014 that the jihadi presence in Syria was becoming more consolidated and had a broader mission:

The moment they finish dealing with Assad, we’re next in line. They are not coming only to fight in Syria.. They are already in the southern Golan Heights, in the area of Dar’a, and this deeply disturbs us, the Americans and the Jordanians. It was notable that at this time, al-Qaeda was also seeking to gain a foothold in the West Bank. Clearly, the stability of all of Israel’s neighbors could be put at risk if this phenomenon were to grow.

The rise of these organizations along Israel’s borders is much more militarily significant than in the past. Prior to the 1990s, the terrorist threat was usually seen in Israel as tactical, while the threat of conventional armies was perceived as strategic. These distinctions no longer make sense. Terrorist organizations are proving far more militarily potent than in the past with the introduction of more advanced military technologies.

Iran Moves In

Finally, Iran has become a new and uncertain factor along Israel’s eastern front, largely due to its role in Iraq, which behaves increasingly like an Iranian satellite state. Despite Washington’s repeated requests that Iraq not persist in this behavior, Baghdad permitted Iranian aircraft to use its air space in order to ship reinforcements to President Bashar al-Assad’s embattled regime in Damascus. The Iraqi regime also supplied Iraqi Shiite militia forces to fight alongside those of Lebanese Hezbollah in Syria against the rebel Sunni forces fighting Assad.

The weakness of the Arab state system has allowed Iran to intervene in a host of internal conflicts and exploit them, from Yemen to Bahrain, Iraq, and Syria. For over a decade, Iranian weapons deliveries bound for Lebanon or the Gaza Strip have been repeatedly thwarted by the Israeli Navy, in ships like the Karine A (January 3, 2002), the Francop (November 4, 2009), or the Klos C (March 5, 2014). Iranian smugglers, backed by the Qods Force of Iran’s Revolutionary Guards, have been active in shipping weapons to aid the pro-Shiite insurgents, known as the Houthis, in Yemen as well.

In December 2013, Bahrain intercepted yet another Iranian weapons ship bringing explosives and weapons to Shiite insurgents. Unfortunately, much of the international community has become accustomed to the deployment of Iranian forces in various combat zones, including Syria. Assuming that Iran invests in upgrading its armed forces, Israel might very well witness the regular deployment of Iranian units in parts of Iraq or Syria in the future, thereby reviving, in part, Israel’s eastern front.

This would allow Iran to project its military power towards Jordan, Israel’s immediate neighbor to the east. Iran has made multiple efforts to build a bridgehead to the Hashemite Kingdom. Since 2012, Iran has sought to reach an agreement with Jordan allowing it to vastly expand Shiite tourism to shrines that are regarded as sacred to Iranian religious pilgrims, particularly near al-Karak in southern Jordan. Today, there is also a substantial Iraqi Shiite refugee population in Jordan. Though not known for religious extremism, this population nevertheless may be targeted by Iranian propaganda.

Finally, radical Palestinian organizations like Hamas and Palestinian Islamic Jihad, which have been allied with Tehran, might be used to build up centers of influence for Iran in Jordan. Israel’s policy of regarding any foreign invasion of Jordan as a “red line” that would trigger its own intervention has provided a certain degree of security for Jordan in the past and has effectively deterred expansionist powers. Were Israel to concede the Jordan Valley and withdraw its forces, then its ability to play this role in regional stability would be much more constrained precisely at a time at which Iranian activism is expected to increase.

Negotiating Defensible Borders

Since 1967, the traditional view in Israel on its final boundaries has been that where Israel has vital security interests in the West Bank, it should seek sovereignty in order to safeguard them. Yigal Allon, known as one of Israel’s greatest military minds, commanded the Palmach strike force of the Haganah during Israel’s War of Independence when he served as a mentor to one of his senior officers, Yitzhak Rabin. During the 1967 Six-Day War, Allon was Israel’s deputy prime minister and in its aftermath he proposed a plan for “territorial compromise” in the West Bank based on Israel retaining 700 square miles (out of 2,100 square miles).

This involved the largely arid eastern zone in the Jordan Valley that would not add any substantial Palestinian population to Israel. By revising the pre-war boundaries this way, Allon concluded that Israel would obtain “defensible borders.” He unveiled the Allon Plan in Foreign Affairs in 1976, in his capacity as Prime Minister Rabin’s foreign minister. Allon explained that any part of the West Bank from which Israel withdrew would have to be demilitarized. The only way to guarantee demilitarization was for Israel to extend its sovereignty to the Jordan Valley.

An alternative way of implementing defensible borders is to insist that an Israeli military presence be maintained in those specific areas in which Israel has vital interests, even if they are not under formal Israeli sovereignty.

Presumably, the security arrangements model would be easier for the Palestinian side to accept in negotiations as opposed to outright Israeli annexation of the area. However, Mahmoud Abbas and the Palestinian leadership were vocally resistant to this model as well, stating a preference for international forces over any IDF presence. Ultimately, Israel will have to seek arrangements for the Jordan Valley that best protect its vital security interests.

Israel’s Bottom Line

Regardless of the question of sovereignty, in the Jordan Valley, Israel must obtain exclusive security control over a specified area, which would allow it to operate effectively against the likely threats. Israel has always based its security in the Jordan Valley on a right of reinforcement in the event that a new threat emerges to the east. This requires that Israel hold on to deployment areas that it may need in the event that those scenarios occur. In an address to the Knesset in October 1995, just before he was assassinated, Rabin stressed that the security border of Israel should be in the Jordan Valley, “in the widest sense of that term.”

One of the main questions for Israel under the scenario of a military presence but not sovereignty, is: How long will it need this military presence in the Jordan Valley? Three years, ten years, or forty years? The answer is not a function of time but of performance: whether the Palestinian security forces can and will fulfill their commitments as outlined in any agreement. West Bank security is also a function of what happens in the surrounding states: Syria, Jordan, Iraq, and Saudi Arabia. Will these states continue to be afflicted with jihadi movements seeking to join their counterparts on the West Bank? Will revived military forces in these areas remain focused elsewhere, or will they coalesce to challenge Israel?

Jordan itself is a factor in Israeli considerations. Any negotiation over the sensitive Jordan Valley requires close consultation with the Jordanian leadership. Moreover, the Sinai precedent must be uppermost in the minds of Jordanian planners. When it became clear that the outer perimeter of the Gaza Strip was completely open through the Philadelphi Route, hosts of jihadi movements relocated to Egyptian Sinai, creating a direct security threat to Egypt itself. Some of the most lethal al-Qaeda affiliates in Sinai relied on Gaza connections.

Ironically, Israeli vulnerability thus undermined the internal security of its largest Arab neighbor. That is a process that Israel cannot allow again in the Jordanian case. For that reason, Israel’s continuing control of the Jordan Valley is not only important for its security, but for regional security more broadly.