What do you do when an ally keeps digging itself into a hole — and is pulling you in with it?

I’m referring to the Israeli leadership, whose policies on the Palestinian issue — including the raid on the Gaza aid flotilla — are achieving the reverse of what’s intended. A relentless focus on military tactics, to the exclusion of long-term political strategy, is isolating Israel and bolstering Hamas.

Israel has legitimate concerns about Hamas militants, who barraged southern Israel with rockets before Israel’s 2009 invasion of Gaza, and who seek Israel’s demise. But a narrow focus on military responses only makes Israel’s long-term security situation more dicey.

As Hamas knows, and the flotilla fiasco shows, this war will be waged in the court of global opinion as much as it is on the battlefield.

The flotilla activists targeted Israel’s blockade of humanitarian aid shipments into Gaza. The Israeli military controls the entry of almost all goods into the strip and lets in sufficient food and medicine. But the list of what goods are or aren’t allowed is arbitrary and constantly changing, making it impossible for Gazans to rebuild their moribund economy. This leaves 80 percent of Gazans dependent on charity — or on Hamas.

For example, the severe limits on construction materials — including cement, which Israel claims can be used for military purposes — have made it almost impossible to repair infrastructure damaged in the 2009 fighting. “I’d say 95 percent of what was destroyed in the Gaza war has not been rebuilt, including apartment houses, homes, schools, hospitals, and clinics,” said Bill Corcoran, the president of ANERA (American Near East Refugee Aid), who just returned from Gaza two weeks ago. ANERA has been trying, with U.S. aid funds, to rebuild a hospital wing, but is stymied because it can’t get the building materials it needs.

Israelis say these controls are a security matter. Yet Israeli officials have made clear that the civilian blockade has political aims: undermining Gazans’ support for Hamas and pressuring the militants to free Gilad Shalit, a captured Israeli soldier. After three years, this policy has not achieved either goal.

Moreover, Hamas has recognized that spotlighting the blockage of civilian goods garners strong international sympathy, and shifts the focus from Hamas’ militancy and failures at governance.

Israel has failed to grasp that the blockade has become untenable; ordinary Gazans can’t be made to pay indefinitely for Hamas’ misdeeds. Such a policy was bound to boomerang against Israel’s reputation — even before the botched raid. It not only soured public opinion in Europe, but also jeopardized a crucial, if troubled, relationship with Turkey, once Israel’s closest Muslim ally.

“There is no question that we need a new approach to Gaza,” a senior Obama administration official told journalists last week. Clearly, the flotilla episode has jolted the Obama team into revisiting the issue; despite the public tough talk, hopefully, the Israeli government will do some deep rethinking as well.

For starters, the administration should urge Israel to end — not just tinker with — the civilian aid blockade. This would remove the rationale for any more blockade-busting ships, such as the Irish vessel Rachel Corrie.

Electronic scanners can be reactivated at crossing points from Israel to Gaza. And observers from the United Nations or international aid agencies can be tasked with accounting for the use of cement and building materials.

Any blockade should target only military weapons. An international naval force could inspect ships bound for Gaza; press reports indicate Israeli premier Benjamin Netanyahu may now be considering this concept — a positive sign.

But this episode should also prod Israel into thinking about the bigger strategic picture. As President Obama said Thursday, “What’s important is that [we] use this tragedy as an opportunity” to open up possibilities for Palestinians, while also meeting Israel’s security needs.

Along these lines, Jerusalem should pay more attention to the policy concerns of the United States, its principal ally. Israel’s swift dismissal of Washington’s proposal for a total settlement freeze undercut U.S. efforts to revive peace talks with more moderate Palestinian leaders on the West Bank and thereby weaken Hamas.

The flotilla fiasco also blindsided U.S. officials; it may hamper U.S. efforts this month to intensify sanctions against Iran — a major administration objective and a key Israeli concern. Mossad chief Meir Dagan said last Tuesday, “Israel is gradually turning from an asset to the United States into a burden.” He may have overstated the case, but Dagan’s words should be taken to heart by his own government.

In today’s world, Israel must work more closely with allies and pay more attention to global opinion — rather than play catch-up after costly errors. Recent events have made the risks of doing otherwise very clear.

— Trudy Rubin is a columnist and editorial board member for the Philadelphia Inquirer. trubin@phillynews.com