A few hours ago, a Palestinian attacker drove a 10-ton Caterpillar front-end loader into a crowded Jerusalem street, upending one bus and smashing into another, crushing cars and slamming into passers-by. By the time a soldier on leave climbed aboard and shot the driver, the attacker had succeeded in killing at least 3 Israelis and injuring at least 40.

It’s still too early to know a lot of details, but according to police officials, the attacker was a resident of East Jerusalem, from the village of Tzur Bacher. One reporter says he is a relative of the attacker at the Merkaz Harav school from a couple of months back.

Although Israel has done a great deal to thwart attacks from Palestinian organizations operating in the West Bank and Gaza, the problem of East Jerusalem is in some sense tougher — and tougher still if it turns out that he, like the attacker at Merkaz Harav, was working alone. Most East Jerusalem Palestinians have Israeli citizenship, carrying the same blue ID that non-Palestinian Israelis do, and have no restrictions on their travel throughout Israel. Most East Jerusalem Palestinians are just regular people with no interest in, or connection to, terror. And to build a wall through Jerusalem, the way Israel has done between its territory and the West Bank, will be tantamount to re-dividing the city — a prospect that few Israelis today are interested in.

In the coming weeks, we’ll be hearing a lot of rhetoric from some politicians about what to do about terror by Israeli Arabs, especially those in East Jerusalem. Putting restrictions on Israeli Arabs’ travel, as Shas leader Eli Yishai has called for today, sounds like the wrong direction for a country that takes pride in its democratic way of life. But this doesn’t make the problem go away. We should expect to hear from Mr. Olmert in the coming hours.