In January 2003, Ariel Sharon won a second term as Israel's prime minister by crushing the Labor party's Amram Mitzna, who had campaigned on a promise of uprooting Jewish settlements in Gaza and surrendering the territory to the Palestinians. Sharon firmly opposed that idea, which he had long regarded as a prescription for disaster. "Evacuating Netzarim," he had said in 2002, referring to one of the Gaza communities, "will only encourage terrorism and increase the pressure upon us."

But within a year of his landslide victory, Sharon turned 180 degrees. To the shock of friend and foe alike, he embraced Mitzna's plan for a unilateral withdrawal. There was no better option, he insisted. As painful as it might be to force 8,000 Jews out of the homes and communities they had built with the encouragement of successive Israeli governments, continuing the status quo would be even worse.

Sharon claims that a majority of Israelis agree with him, but it is impossible to know, since he has refused to put the issue to a popular vote. Last week, Israel's parliament backed him up, voting down a proposal to hold a national referendum on what Sharon calls the Gaza "disengagement". Barring the unexpected, then, the Jews of Gaza will be expelled this summer as Israel's prime minister carries out the very plan he was elected to prevent.

The supporters of withdrawal make a plausible case. Defending the Gaza settlements exacts a heavy military and financial cost, they say, tying down far too many soldiers to protect relatively few civilians. Pulling out of the territory will shorten Israel's line of defense. And once Gaza's Jews depart, the terrorists will be deprived of victims to attack, thanks to the security fence that seals off the territory from Israel proper.

To many Israelis, leaving Gaza also promises psychological relief -- an end to the exhausting and unwanted burden of militarily ruling a hostile population. Norman Podhoretz, writing in the current issue of Commentary, quotes the blunt comment made to him by one Israeli at a high-level conference in 2003: "Why should we keep trying to negotiate peace with people who want only to murder as many of us as they can? Instead of going on with this charade, the best thing we can do is cut ourselves off from them with the fence and then let them stew in their own juices."

But the world doesn't work that way.

To retreat in the face of terror is to invite more of it, not less. Handing Gaza over to the gangsters of Hamas and the PLO will not leave them "stewing in their own juices", but celebrating their victory. As they take over the houses, farms and schools of the people they demonized and terrorized for years, they will draw the obvious conclusion: Violence works and the Jews are on the run.

Listen to Ahmed Al-Bahar, a top Hamas operative. "Israel has never been in such a state of retreat and weakness as it is today following more than four years of the intifadah," he exulted. "The withdrawal marks the end of the Zionist dream and is a sign of the moral and psychological decline of the Jewish state."

Just as Israel's unilateral withdrawal from southern Lebanon in 2000 proved a triumph for Hizbullah, so will Fatah, Hamas and Islamic Jihad revel in Israel's surrender of Gaza. The Lebanon retreat inspired the Palestinian Authority to launch a murderous terror war, the so-called "second intifadah". What fresh hell will the Gaza disengagement inspire?

A few days ago, Israeli officials learned that Palestinians had smuggled SA-7 antiaircraft missiles into Gaza from Egypt. Mahmoud Abbas, the "moderate" Palestinian president, announced plans to release two hard-core terrorists from custody. Far from cracking down on Hamas and Islamic Jihad, Abbas is taking them on as partners: the official Palestinian media reported that the two terror organizations intend to formally join the PLO. "What's happening now isn't considered a calm," the leader of yet another terror squad, the Al-Aqsa Martyrs Brigade, told an Israeli newspaper, "It's merely a warrior's rest."

If the terrorists are this brazen now, when Israeli troops are still on the ground, what will happen when those troops are gone and Gaza becomes a safe haven for killers and radicals?

It isn't only Israel that will pay the price. "A Hamas flag over Netzarim will justify 37 years of terrorism," writes Michael Rubin, the editor of the Middle East Quarterly. An Israeli withdrawal will embolden rejectionists across the region. "If terrorism can free Gaza, why not the West Bank, the Galilee, Indian Kashmir, or democratic Iraq?" Rubin asks.

Wars are not won by retreats, or with fences, or through the ethnic cleansing of Jews. Difficult as the Gaza status quo may be, what is scheduled to take place this summer will prove far worse. Sharon -- the old Sharon -- had it right: Unilateral withdrawal is a prescription for disaster.

[This article originally appeared in the Boston Globe on Thursday, March 31, 2005.]