JERUSALEM -- As a piece of engineering, the Palestinian-made Qassam rocket is like a bad high school science project. A thin steel tube with four metal fins, propelled by a mix of sugar and fertilizer, it carries a crudely fashioned warhead. With no guidance system, the rockets are so inaccurate that they are often dismissed as nothing more than "flying objects."
But as a weapon against Israel, the Qassam is worthy of a top prize. Cheap and plentiful, the homemade rockets - though rarely deadly - have proven to be highly effective at forcing thousands of Israelis from their homes, throwing the Israeli government off balance and leaving the modern, high-tech Israeli military helpless to stop them.
"It's very simply made. The sugar they buy from Israel. The fertilizer they buy from Israel. The metal pipe they buy from Israel. Ingenious. Very ingenious. I take my hat off to them for how to make simple things into deadly weapons," said Uzi Rubin, former director of Israel's missile defense organization.
During the past three weeks, Palestinian militants have fired about 270 rockets, with a range of about six miles, into Israel, many of them striking the southern Israel working-class town of Sederot, about one mile from the Gazan border. Two people have been killed in Sederot, and, by some estimates, more than half the town's population of 24,000 has fled.
Israel has responded with dozens of punishing airstrikes, destroying training facilities, launch sites and other militant targets. More than 50 Palestinians have been killed.
Still, the Qassams keep falling, including three yesterday.
According to an intelligence briefing given to the Israeli Cabinet this week, Gaza militants have smuggled in rockets with a range of up to 10 miles, bringing larger cities such as Ashkelon within range.
For Hamas, the rockets have helped unite Palestinians during a time of factional violence between members of Hamas and Fatah in Gaza. The attacks also continue to receive backing from some Palestinians.
A recent poll conducted by An-Najah National University in Nablus found that 51 percent of Palestinians support the rocket attacks and 43 percent oppose them. Some 32.5 percent said the rockets served the interests of the Palestinian national struggle; 40 percent said they hurt the struggle, and 23 percent said the attacks are useless.
Jabril Rajoub, former Palestinian national security adviser and member of the rival Fatah movement, said the violence in Gaza since the Israeli withdrawal in 2005 has only damaged the Palestinians.
"I'm not proud of the model of Gaza," he said. "Instead of becoming like Singapore, it became like Mogadishu."
The first Qassam rockets were launched in 2001, but because of their short range, they fell in Gaza. As the rocket designs improved in 2002, they started landing in Israel. According to the Israel Defense Forces, more than 6,500 rockets have been fired at Israel, killing 14 people.
Meeting this week to discuss responses to the rocket fire, the Israeli government vowed to wage a sustained campaign of airstrikes against militants in Gaza and limited ground incursions into the edges of Gaza where militants sometimes launch rockets. Israeli Prime Minister Ehud Olmert said military operations had been successful in reducing rocket attacks and wearing down Hamas, the main militant group responsible.
But in announcing its response, the government stopped short of ordering a full-scale invasion of Gaza, as many members of the Israeli right called for this week.
Such an offensive would no doubt be costly, endangering civilians and soldiers and offering no clear exit out of Gaza. Israel is wary of repeating the mistakes of last summer, when the government ordered troops into Lebanon and failed to halt the shower of Hezbollah rockets.
But without a clear answer to the rockets, Israeli leaders face an increasingly disgruntled public.
In a Tel Aviv public park, several hundred Sederot residents have taken shelter in a tent city calling attention to the Olmert administration's failure to solve the rocket threat.
Scrambling for new ideas, some hawkish members of government proposed this week that Israel should build its own Qassam rocket and fire it into Gaza anytime a rocket lands in Sederot. Other suggested that Israel should sever all ties with Gaza.
"Since we talked about disengagement and we implemented disengagement, we have to disengage totally from Gaza, to cut off Gaza from Israel, to cut off Gaza from Judea and Samaria" - using the biblical terms for the West Bank - "and to find someone willing to take the responsibility," Strategic Affairs Minister Avigdor Lieberman told Israel Army Radio this week.
Earlier this year, the Israeli defense ministry selected a system known as "Iron Dome" to intercept Qassam rockets and the other short-range rockets like Katushyas, which Hezbollah used in its war against Israel last summer. But the system will not be operational for about three years.
In the meantime, there is no other effective way to halt the rockets or curb the suspected flow of more lethal weapons into Gaza without a large-scale invasion, says Shlomo Brom, a military analyst and former general at the Institute for National Security Studies at Tel Aviv University.
But Brom, writing in an article released this week, warned that the price would be high in terms of casualties of both soldiers and civilians because such a military operation would prompt even more rocket fire.
Then there is the question of whether Israel would want to take on the responsibility of occupying the Gaza Strip - less than two years after evacuating it.
"In light of the limited damage caused by the export of violence from the Gaza Strip," he wrote, "Israel would do well to be cautious and not succumb to the illusion that there is a comprehensive solution to the Gaza Strip problem. It is not clear what advantage Israel enjoys if dragged back into the Gaza Strip."