AFTER three years of campaigning for Israel to lift the siege of Gaza, some of the Islamists ruling the territory are having second thoughts. This week the agriculture minister for Hamas, the Islamist group that runs Gaza, was putting the finishing touches to a ten-year plan to wean it off dependence on Israel and make it self-sufficient in food. Israel’s ban on fertilisers had helped his plan to replace fertiliser with compost made from sewage that otherwise spills into the sea, and turn Gaza into a big organic farm. Then Binyamin Netanyahu, Israel’s prime minister, promised to open the crossings. Some Gazans fear that Israeli merchants will sell cheap produce in Gaza, as they used to before the siege.

The minister, Muhammad al-Agha, says he is undeterred. To protect his farmers, he has told Gaza’s importers to buy licences each time they bring in Israeli foodstuffs they import. Garlic, which Gaza lacks, will be let in but no vegetables grown in Gaza. And once he realises his plan to plant a million fruit trees, he will ban fruit imports too.

But keeping Israel’s supplies out will be hard. After three years of reliance on underground smuggling from Egypt, Gaza’s merchants are again buying Israeli. Since Mr Netanyahu’s promise to ease the blockade, an eerie silence has fallen over Gaza’s border with Egypt, which hitherto echoed to the whirl of a thousand winches hauling goods to the surface. Now shopkeepers fear being lumbered with shelves of unwanted tunnel-tattered products, as Israel’s neater goods pour in. In the past, underground traffickers would have organised one of Gaza’s fighting groups to attack an Israeli position in order to provoke a closure and keep trade from Egypt flowing. But as part of its informal non-aggression deal with Israel, Hamas is policing the border and pounces on anyone operating without its consent.

So some tunnellers, burdened by Hamas taxes and market saturation, are closing down. Others will survive: Marlboro cigarettes from Egypt are half the cost of Israel’s version, even after Hamas’s tax. Egyptian petrol is cheaper still. Hamas may also keep tunnels open for weapons. The burrows are a conduit for cash, too.

Other factors will keep the tunnels working. Israel has yet to spell out what it will let in by land. Tony Blair, Britain’s former prime minister, who claims credit for negotiating the deal as the envoy for the Quartet (the UN, the EU, the United States and Russia), says he will not get the small print for two weeks. As the crisis following Israel’s recent bloody interception of a siege-busting flotilla fades from the headlines, the pressure on Israel eases and its leeway for backsliding widens.

Meanwhile, lest Israel and its allies try to prise the economy away from it, Hamas is tightening its hold over supplies by land. It has stiffened customs and passport checks and is limiting exit permits for merchants. It is also restricting the import of goods, such as fizzy drinks, which it has learnt to manufacture under the siege. And Hamas is looking at ways to profit as much from formal trade as they do from informal. “We’re clever enough to understand the multiplier effect,” says a Hamas man.

Western governments and nearby anti-Islamist ones, such as Egypt and Jordan, are wary of rushing in. When Hamas won power at the ballot box in 2006, Palestine’s foreign paymasters cancelled all development aid, limiting help to humanitarian supplies. Israel’s blockade prevented the West from sending material for reconstruction. Western governments have suggested operating through go-betweens such as the UN. But Mr Blair talks to people in Gaza only via video-conference.

So the West’s regional allies are keeping their distance. Mahmoud Abbas, who professes to be president for all Palestinians, stays away. Egypt’s state security service still denies visas to Gazan businessmen. Amr Moussa, the 22-state Arab League’s secretary-general, paid a rare visit to Gaza earlier this month but met Hamas officials as members of a faction, not as Gaza’s official authority, and asked Hamas’s security guards not to escort him. Even if Israel opens the crossings, some of the siege’s harshest aspects will stay. Exports are banned, the naval blockade is still in place, and most Gazans cannot yet freely come and go. “We don’t need mayonnaise,” says a Gazan, who recently heard him speak. “We need freedom.”

Yet even the promise to open the crossings marks a watershed. Israel must realise that its closure has failed to bring down the Hamas regime. Increasingly, international envoys ask whether an economic opening to Gaza could lead to a political one. Mr. Blair repeatedly says he would love to visit. The longer he stays away the more diplomatic ground he and the West seem to lose to Hamas and its friends.

The Turkish Islamist group that helped organise the bloodied flotilla is trying to invest in rebuilding Gaza’s port and generally bolstering Turkey’s role in the territory. American investors of Palestinian origin are set to open Gaza’s first mall. Land prices in Gaza city have shot up. Saudi investors have asked management consultants to look for opportunities.

For Mr. Abbas’s Palestinian Authority, things look bleak. Its supporters complain that Hamas has shifted world attention from core issues such as Palestinian refugees and the status of Jerusalem, which Mr Abbas is trying to focus on, to those mayonnaise supplies for Gaza. Israeli officials this week approved the demolition of a score of Arab homes in Jerusalem beneath the most contested ground in the occupied territories, the Old City’s al-Aqsa shrine which the Palestinians prize as part of their hoped-for capital and Israel reveres as the Temple Mount. As Mr Abbas loses ground, Hamas gains it—and consolidates.