THE HAMAS movement provided a dramatic illustration yesterday of its ability to disrupt any movement toward peace between Israelis and Palestinians. As tens of thousands of residents of the Gaza Strip surged across the border into Egypt, Hamas security forces directed traffic; earlier, they stood by as organized groups of militants blew up the fence along the previously sealed border. As Hamas no doubt expected, the government of Egypt greeted this illegal invasion with a quick surrender: President Hosni Mubarak announced that Gazans would be allowed to shop in Egypt because they "are starving due to the Israeli siege."

In fact, as Mr. Mubarak well knows, no one is starving in Gaza -- though food, fuel and cigarettes are much cheaper across the border. Israel closed its border with the territory and disrupted power supplies over the weekend in response to a massive escalation of Palestinian rocket launches from Gaza at nearby Israeli towns -- between Tuesday and Saturday last week, some 225 rockets were aimed at the town of Sderot, where more than 20,000 Israelis have been relentlessly terrorized. Hamas took advantage of the blockade first by arranging for sympathetic Arab media to document the "humanitarian crisis," then by daring Egypt to use force against Palestinian civilians portrayed as Israel's victims. Its ultimate goal, stated publicly yesterday by Damascus-based leader Khaled Meshal, is to force Egypt to permanently reopen the border in cooperation with Hamas; that would greatly diminish Israel's ability to respond to rocket attacks with economic sanctions, and it would undermine the rival Palestinian leadership of Mahmoud Abbas.

Mr. Abbas and Israeli Prime Minister Ehud Olmert committed themselves to reaching a peace accord in 2008 during President Bush's visit this month. Yet since then, political attention in the region has been focused on the rocket attacks, Israel's retaliatory strikes against militants in Gaza and the subsequent blockade, and yesterday's dramatic breach of the border. Naturally it is impossible for the peace negotiations to make progress in these conditions. So those who say their priority is an Israeli-Palestinian settlement ought to be trying to stop Hamas's disruptions.

That obligation doesn't just fall on Mr. Abbas and Mr. Olmert -- though Israel may have a lesson to learn from the way Hamas exploited its temporary shutdown of fuel supplies. Mr. Mubarak and other Arab leaders have to resist the urge to roll over every time they are challenged by Hamas and al-Jazeera television. Would Mr. Mubarak allow tens of thousands of Darfur refugees to illegally enter Egypt from Sudan, where a real humanitarian crisis is underway? Surely not. Egypt's obligation as a law-abiding state is to restore order on the border and prevent the ongoing and massive smuggling of armaments into Gaza. That would go a long way toward stopping the rockets.

The Bush administration and European governments should act to stop the ongoing farce at the U.N. Security Council and the U.N. Human Rights Council, which have ignored months of daily rocket attacks aimed at Israeli civilians but now rush to condemn a partial, three-day disruption of Gaza's power supplies. Hamas, and the people of Gaza, should get a consistent message that relief lies not in blowing up international borders but in ending attacks on Israel and allowing a peace process to go forward.