For years, Israel and the United States have been urging Egypt to do more to halt the illegal trade—in guns and rockets, but also in fuel, cement, and consumer goods—under the 14 kilometer-long Sinai-Gaza border. Post-Mubarak Egyptian governments have been more willing than the regime of close ally Hosni Mubarak to go after the tunnels. It is not that Egypt decided to act against the tunnels in an effort to maintain security along the Israeli border alone; rather, changing circumstances made it abundantly clear to Egypt’s generals that the tunnels have become a direct threat to Egypt’s national stability.

Starting with the August 2012 massacre of 16 Egyptian soldiers in Sinai, Egypt’s national security establishment realized that the flow of weapons and fighters can travel in both directions. Since June 2013, in the lead up to President Mohamed Morsi’s ouster in Cairo, the Egyptian military has maintained its most effective operation yet against the tunnel network.

Looking forward, though, it is unclear how long Egypt can sustain the current success in tunnel closures. Furthermore, there is no indication that Cairo is considering policy options to keep the tunnels closed for the long term once the military withdraws from the border.

The smuggling tunnels emerged as a problem in 2005, when Israeli forces withdrew from Gaza; and smuggling expanded significantly following the 2007 takeover of the strip by Hamas and the subsequent Israeli policy of limiting imports and exports. However, the quantity, lethality, and capabilities of smuggled weapons increased following the Arab uprisings: whether this was in the importation of Fajr-5 rockets from Iran or man-portable air-defense systems and other anti-aircraft systems from Libya.

After the August 2012 attack, the Egyptian armed forces initiated efforts to block or destroy tunnels under the Gaza border as part of Operation Eagle, a larger operation begun in 2011 to counter the Salafi-jihadi threat in Sinai. However, the methods used had little effect on smuggling, and underground trade continued normally. Of the almost 250 tunnels Egypt covered or destroyed that year, more than half were back in operation shortly after the military left the site.

In the following months, Egyptian leaders concluded that the tunnels contributed to threats to national security and the continued instability in Sinai. Egyptian military, intelligence, and political leaders may have been willing to turn a blind eye to Palestinian smuggling of food, fuel, and building materials—accepting that occasionally weapons got through as well. Risking Egypt’s own security, however, was another matter. As Essam al-Haddad, a top Morsi advisor and Brotherhood leader, said at the time, “We don’t want to see these tunnels used for illegal ways of smuggling either people or weapons that can really harm Egyptian security.”

With this new realization, Egypt advanced its efforts. According to a January 2013 Israeli report, “U.S. technological measures made available for Egyptian use … and intelligence cooperation” were enabling Egypt to prevent “large-scale smuggling of weapons into Gaza.” In addition to counter-smuggling interdictions, Egyptian operations to destroy the tunnels themselves began in earnest in February 2013. Unlike previous efforts, which could be easily reversed, from February forward the Egyptians actually flooded tunnels, which degraded their structure and stability.

In addition to taking action on its side of the border, Egypt also has used its leverage over Hamas to encourage action inside Gaza. For instance, after the August 2012 attack on Egyptian soldiers—despite Hamas claiming this had nothing to do with Gaza—Egyptian influence saw that Hamas promptly closed the openings on its side of the tunnels. Hamas did so again in the wake of the May 2013 kidnapping of Egyptian security forces: declaring the entire border area a “closed military zone.”

In the month prior to Morsi’s removal, Egyptian forces again stepped up their campaign against the Gaza tunnels. By one measure, the amount of fuel entering Gaza through the tunnels in the last week of June 2013 was around 10 percent of that entering at the beginning of the month. According to the United Nations Office for the Coordination of Humanitarian Affairs (OCHA), “These amounts were the lowest recorded since August 2012.” This suggested that Egyptian forces indeed had the capability to effectively shut the tunnels, and it was the will to act that stopped them from doing so previously—when such action was not yet perceived as protecting Egyptian sovereignty and stability.

In the first week of July, when the military removed Morsi from power, OCHA estimated thatfewer than ten tunnels were operational. By the end of August, Raed Fattouh, president of the Palestinian Authority’s coordination committee for the entry of goods to Gaza, said that Gaza’s tunnels were only functioning at 30 percent of their capacity. Even with this slight easing, the tunnels have yet to return to their post-Mubarak traffic.

The post-Morsi counter-tunnel operations have also been the most sustained effort to date. Estimates of the number of operational tunnels in June 2013, before the latest crackdown, range from below 100 to as many as 220 or even around 300. By late September only around ten were open. According to another report, fuel was still being smuggled through the open tunnels—at less than half the rate as during early 2013—but exclusively for the use of Gaza’s power station. In late September, the spokesman of the Egyptian armed forces said Egypt had destroyed the effectiveness of the tunnel network. The Egyptian military also announced that it would establish a “buffer zone” along the Sinai border.

Destroying tunnels, though, requires constant vigilance. Earlier this month, the Egyptian military claimed to have destroyed almost 800 tunnels in 2013. In January 2013, however, Egyptian journalist and Sinai expert Mohannad Sabry estimated there were around 250 operating tunnels, which suggests that Egyptian forces are continuously closing the same tunnels. While highly effective in the short term, consumer and humanitarian demand inside Gaza ensures that tunnel trade will resume the moment Egyptian forces back away. Regular Egyptian activity on the Gaza border is also a worry for Israel, which has long enjoyed Sinai as a buffer between its forces and the Egyptian’s. Egypt and Israel—which approves any Egyptian deployments that would exceed peace treaty limitations—must decide if such operations are a long-term solution or else consider other options for decreasing the extent of the Gaza tunnel network.

Finally, Egypt and Israel seem to agree on the need to clamp down on the Gaza tunnels. Moving forward, the two will need to determine—together—the best way to address this challenge.

This article is reprinted with permission from Sada.  It can be accessed online at: http://carnegieendowment.org/sada/2013/10/22/tunnel-vision/gqxp

Zack Gold is a Washington-based Middle East analyst and author of the Brookings Institution’s Saban Center analysis paper “Sinai Security: Opportunities for Unlikely Cooperation Among Egypt, Israel, and Hamas.”