One needs only to look at the 1973 Yom Kippur War to see exactly how imperative the Golan Heights are for the defense of Israel.
The Israelis held the Golan Heights at the outset of that war. The topography of the Heights allowed Israel to guard that entire section of the border with about two hundred tanks. As it happened, when Syria attacked without warning on October 6, there were only about 160 serviceable Israeli tanks on the line.
The Syrians attacked with 1,400 modern tanks. For 48 hours, the Israelis delayed the attack by utilizing prepared positions and slowly, inevitably releasing ground. The terrain allowed the Israelis to maneuver without being directly exposed to Syrian anti-tank weapons.
The only reason why Syrian armor wasn’t on the outskirts of Tel Aviv by October 8 is because the topography of the Golan Heights provides only two gaps through which armor can reliably travel. One is now known as Emek Habacha, the “Valley of Tears,” and it was through this gap that the Syrians concentrated. It is only about seven miles wide. About 100 Israeli tanks were engaged there, and ninety-three of them were destroyed before reinforcements arrived. In 1973, Israeli armor held no significant advantage over that of Syrian armor. Geography was the only thing in their favor.
The Syrians actually invested most of the Heights and had begun to push into the valley below before the Israelis counterattacked and drove them back (unlike the Israelis, the Syrians did not have the luxury of prepared positions). The Israeli counterattack was nevertheless extremely costly, because the Syrians made excellent use of infantry anti-tank and -aircraft weapons.
Most of the Israeli tankers engaged in the Valley of Tears were killed or wounded, and the crisis did not end when mobilization kicked in because the situation was so dire that the relief arrived piecemeal and was as often as not destroyed as soon as it was fed into the line. It is really quite impossible to overexaggerate how desperate the situation was for them; the Israeli forces were within hours of cracking completely.
It is also worth noting that the Israelis were able to mobilize more effectively because of the holiday. Most of the Israelis were at home, and therefore were able to quickly join their local reserve units and move out within two days. The Syrians will never forget that mistake, I can assure you.
In Israel’s brief history, Syria has used the Golan Heights as a springboard for invasion twice and was planning to use it a third time when they were preemptively attacked (1967). Throughout the mid-1960s they allowed Yassir Arafat’s al-Fatah to use the Heights as a platform from which they shelled and sniped the valley below.
The Israelis to not control the entirety of the Heights, but only to just past the most prominent ridge line. The gaps work in both directions; an Israeli attack on Syria today would have to penetrate a U.N. security zone, followed by a frontal assault on prepared Syrian positions, constricted by the same geographical features that led to the Syrian defeat.
As it is, both sides can now guard approximately twelve miles of territory. If either side controlled all of the heights, the other would instantly be required to guard something like forty-five miles of territory which would be observed from superior positions. Virtually all of the non-Israeli inhabitants of the region fled the area in 1967 to Lebanon and Syria, and have long since made other living arrangements. Aside from water rights, there is no reason for Syria to wish for the return of the territory, save one.
I’ll let you guess what that one reason might be.
References:
http://www.freeman.org/m_online/langfan/langfan5.htm
http://i-cias.com/e.o/golan_h.htm
http://www.us-israel.org/jsource/Peace/golan_hts.html
http://www.jpost.com/Editions/2000/01/13/Tourism/Tourism.1253.html