Imagine, if you would, that the catastrophe of Sept. 11 was only one of many on our soil.

Imagine if, the previous June 4, you had turned on your television to hear that al-Qaida, in a coordinated attack, had sent 20 suicide bombers to mingle with crowds in and around dance clubs throughout America. And now the television was reporting that more than 1,000 young Americans had been killed.

Witnesses described teen-agers being hurled through the air. Pieces of flesh were found as far as a block from where the explosions occurred. Shrouded bodies were photographed lined up on glass-strewn sidewalks.

The next day, there was an interview overseas with the father of one of the bombers. “I am very happy and proud of what my son did,” the father said.

Imagine then, on Aug. 9, 2001, that another dozen suicide bombers sought out big, popular family restaurants around America. More than 750 people were killed, including 300 children. The bombers, it seemed, had packed their explosives with pieces of metal, and survivors were shown with nails still embedded in their faces and around their eyes.

And imagine, if on Sept. 9, two days before the Trade Center attacks, more suicide bombers had gone into Union Station in Chicago, mingling with the crowds. This time, 150 were killed and 3,000 injured by nails, falling debris and flying glass. Windows were shattered for blocks, and rescue workers were so overwhelmed that stunned, bleeding victims were found walking outside in the rain.

Imagine if less than two weeks later, they chose to target malls. They did so on Dec. 10, picking a time when shopping centers would be jammed with holiday crowds. This time, they coordinated in pairs, placing themselves at opposite ends of concourses, so that as people ran from the first explosion, they were killed by a second.

By the time the bodies had been counted, 1,000 Americans were killed in the mall bombings. There were terrible witness accounts, many of them similar descriptions of adults and children lying on the ground with both legs blown off, bleeding to death before rescue crews were able to arrive.

Imagine also that after each catastrophe, people in extremist neighborhoods abroad celebrated the bombings, shooting guns in the air and handing candy to children.

By now, American security people managed to stop many would-be bombers, who then blew themselves up at checkpoints.

But others kept at it, such as on March 2, 2002, when a cell sent members into busy neighborhoods, killing 500 Americans, a third of them children and infants. There were eerily similar reports of severed heads seen rolling away from the blasts.

The most poignant stories in the media were about families that were wiped out  parents and kids killed eating at restaurants, or strolling through malls. Support groups were started among widows and widowers left suddenly alone, without spouse or children.

And then it seemed to accelerate, when 1,000 were killed as they sat down to banquets this past March 28, and 100 outside grocery stores on March 29, and an additional 750 killed at restaurants on March 31. The wounded had to be triaged in hospital cafeterias, even churches and schools.

Imagine if these were the worst of the incidents, but that in the last 18 months, there were a total of 50 suicide bombings in America, with the smaller death counts between 50 and several hundred.

Imagine, finally, that almost every case involved not just civilians, but young people and families, just going about their daily lives.

If you can imagine these things, then you can imagine what life has been like in Israel, where the Jewish population is roughly a one-fiftieth of America’s population. Do the math, and every time 10 are killed there, it’s like 500 here. The dates I’ve used were the same that saw bombings in Israel.

Imagine what that would have been like here.

And imagine how we would respond.