There is no doubt where the border lies between Israel and Lebanon: The Israelis have erected a tall, taut fence of 20 strands of piercing barbed wire. Coils of razor wire run parallel on both sides, three deep, as far as the eye can see.
The barbed wire is electrified. Any breach is known immediately, and Israeli troops can pinpoint the violation in seconds.
The menacing apparatus was built to keep unwanted Lebanese out of Israel. But in the view of the United Nations Interim Force in Lebanon (UNIFIL), it has done little to keep the Israelis in.
That point was emphasized Tuesday, when - after a day of heavy fighting in Southern Lebanon - two Israeli helicopters loaded with troops and ammunition and headed for the self-declared "security zone" collided into each other, at Shuar Yishuv near Kiryat Shmona, killing 73.
The incident - the worst military crash in Israel's history - will sharpen an already growing debate in Israel about its occupation of southern Lebanon.
"There is no tool, no trick ... the Israeli Defense Forces haven't tried in order to reduce the losses of this war, but the war keeps winning," the Yediot Ahronot newspaper commented yesterday.
However, Prime Minister Benjamin Netanyahu said he would not change the policy in Lebanon. "We are not going to be deterred, and we are not going to relent," Mr. Netanyahu told reporters after touring the crash site.
But even before the crash, Israel's minister of public security, Avigdor Kahalani, called for unilateral withdrawal. "Israeli soldiers are like [sitting] ducks," he said earlier this week after three Israeli soldiers were killed by a guerrilla bomb.
"The Israelis are in the wrong country, to start with," says Timur Goksel, the UNIFIL spokesman. "They are anxious for their soldiers, but they are in the wrong country."
Set up in 1978, UNIFIL has one of the most political mandates ever bestowed by the UN Security Council: to confirm an Israeli troop withdrawal from the area and help Lebanese authorities in Beirut resume control.
After nearly 20 years, the UN mission requires tact and doublespeak more than ever. But along the last active front line of the Arab-Israeli conflict, there is little doubt who is the occupying force.
The Israelis call the strip of land they occupy a "security zone" and say their presence protects northern Israel from attacks by Islamic resistance guerrillas such as Hizbullah, supported by Iran, and Amal.
In Israeli eyes, the zone is packed with "terrorists." The Israel-created militia is euphemistically called the South Lebanon Army (SLA). It has been known to conscript Lebanese men as young as 14, who are then forced to fight the guerrillas, their countrymen.
For UNIFIL, part of the game is a mixture of semantics and an alphabet soup of which George Orwell would be proud.
It is a legal indulgence, because of UNIFIL's uniquely political mandate. Other UN "peacekeeping" forces deployed around the world, often as buffers between warring factions, have orders to maintain strict neutrality.
"For us to call it a 'security zone' would be a slap in the face to people here, because for them it's an 'insecurity zone,' " says one Norwegian UN officer.
Instead, occupied territory is called the ICA, or "Israel-Controlled Area." The SLA is referred to as the DFF, the "de facto force" on the ground; and until recently Israeli military positions were named PVs, or "permanent violations" of Lebanon's borders.
Hizbullah and other guerrilla groups are called the IR, "Islamic resistance," or simply AEs - "armed elements."
The Israelis have blurred lines of reality further, however, by painting some of their vehicles UNIFIL white. The UN has made official complaints for more than a year, but to no avail.
Though few rules apply to the fighting forces, the opposite is true for Lebanese civilians who remain in the occupied zone.
Many say that their lives are compromised: They are abused by the Israelis and the SLA as collaborators with Beirut; and they are likewise suspected by Beirut of collaboration with Israel.
Among the most grating Israeli rules is that, north of the electrified border fence, in Lebanon, every civilian car must carry two passengers to minimize the risk of solo Hizbullah suicide bombings.
"There are very strict rules, and we are occupied," says a Lebanese woman who asked not to be named. "We are living in a big prison."