The news Wednesday that Israeli warplanes bombed Palestinian supply tunnels running into the Gaza Strip again is more than a predictable hiccup in Israel's self-declared cease-fire. A Palestinian bomb had killed an Israeli soldier on Tuesday. Israel responded with airstrikes the same day, and followed up Wednesday with air attacks on tunnels in the southern Gaza town of Rafah, on the Egyptian border. There were no reported casualties, but residents fled their homes in panic.

The raid underlines - if any underlining was needed - that any lasting truce is going to hinge on the question of what is allowed into Gaza and how.

Since Israel stopped allowing much except humanitarian supplies into Gaza two years ago, in a bid to undermine the strip's Hamas rulers, Gazans have depended on a warren of tunnels from Egypt for everything from AK-47s to cheese. If they couldn't get even legit stuff in through the Israeli-controlled border points, Gaza's merchants have been bringing it in underground. And Hamas's rocket builders have been bringing their weapons in that way, too.

The Israeli government's effort to starve Hamas out seems to have failed (partly because of the tunnels). Its recent effort to bomb Hamas out (and the tunnels) does not appear to have been much more successful. The Islamist party/army is bloodied but unbowed, and almost as soon as the guns fell quiet at the end of the recent war, Palestinians were digging again.

You can hardly expect Gazans to go on living only on smuggled goods, especially now that they have so much to rebuild. Nor can you expect the Israelis to allow Hamas to resupply its rocket stocks. If Israel wants international monitors to stop the tunnel traffic, the world is probably going to insist that Israel open its border crossings in return.