What happened yesterday at the Hawara checkpoint south of Nablus makes clear the sort of problems the IDF now faces in the West Bank in its war against suicide bombers.

The checkpoint was closed to Palestinian traffic around 9:30 A.M., and the army stepped up its searches after getting intelligence about a lone suicide bomber. In the search, the soldiers came across a Palestinian youth carrying a fake bomb. Intelligence officers say the terror groups are once again testing the soldiers for their alertness.

If the youth had reported he managed to get through safely, the terror group would have assumed the route was clear to send suicide bombers into Israel. But less than two hours later, another youth, also from Nablus, blew himself up in Carmel Market.

Initial investigation of the attack suggests the bomber passed through the Hawara checkpoint early in the morning, a few hours before the soldiers closed it. Nablus is surrounded by checkpoints and army forces, in a way that enables nearly hermetic closure of the city in case of an alert about a bombing.

But the Hawara checkpoint is the main exit from the city, under constant watch by media and human rights groups. The decision to close the checkpoint means total disruption of the lives of thousands of Palestinians, who mostly have nothing to do with the terror.

If necessary, the army deploys a kind of network of checkpoints, meant to trap suicide bombers on their way to Israel. But when there is no alert, the net is not deployed - and yesterday there was no net.

The use of a youth, in this case a 16-year-old, is no longer unusual. The organizations know the soldiers aren't as punctilious with children and women as they are with adult men. A child does not even have an ID card, so it is difficult for the soldiers to even identify the child as being the subject of an alert.

There aren't enough women soldiers at the checkpoints to check every woman passing through. That's why more than ten children have been sent through Haware carrying bombs, and since September, the army has arrested 16 Palestinian women, mostly from Nablus, on suspicion that had volunteered to participate in suicide bombings.

The launch of the two boys yesterday, one carrying a fake bomb, the other a real one, is evidence of just how far the groups are ready to invest in their efforts to conduct terror attacks. Nearly every day, the Shin Bet and IDF manage to foil attempted suicide attacks, planned in the West Bank with Tel Aviv or Jerusalem as the target.

One question discussed yesterday in the media was the connection, if any, between the attack and Arafat's hospitalization. It is not at all certain that Arafat's medical condition was a consideration for the people who launched the teenage suicide bomber.

The routine of trying to conduct an attack was more likely the motivation. They've been doing it for three years and without explicit instructions to do otherwise, they'll continue trying to produce terror attacks.