After Hamas seized control of the Gaza Strip in 2007, Israel  with Egypt’s help  imposed a blockade on many goods and most people going into and out of the territory. The goal was to quickly turn residents against their new government. Three years later, Hamas is still in charge  and the blockade has become an excuse for any and all of the government’s failures.

The situation in Gaza is grim. Eight out of 10 people depend on international aid agencies to survive. Basic foodstuffs are available, but medical supplies and construction materials are severely lacking. The desperation could be seen on Tuesday when Egypt lifted the blockade and several thousand Gazans rushed the border but were later sent home after police officers said they did not know when the crossing would be opened.

On Tuesday, President Obama expressed his “deep regret” over the flotilla incident. He is doing Israel no favors with such a tepid response. Prime Minister Benjamin Netanyahu has shown time and again that he prefers bullying and confrontation over diplomacy. Washington needs to make clear to him just how dangerous and counterproductive that approach is.

Mr. Obama needs to state clearly that the Israeli attack was unacceptable and back an impartial international investigation. The United States should also join the other permanent members of the United Nations Security Council  Britain, France, Russia and China  in urging Israel to permanently lift the blockade.

That would lessen the suffering of the people in Gaza. And it would give the United States more credibility as it presses both Israelis and the Palestinian president, Mahmoud Abbas, to negotiate a peace deal.