Hamas probably can’t believe its luck — or the lack of moral seriousness by its enemies. The terrorists murder six Israeli hostages, including one dual-citizen American, and Israel is suddenly under pressure to make concessions—to Hamas.

That’s the way it looked Monday, a day after Israel said it recovered the bodies of six hostages. They were executed in a Gaza tunnel only a day or two before Israel reached them, shot multiple times at close range. The hostages are Eden Yerushalmi, age 24; Ori Danino, 25; Alex Lobanov, 32; Carmel Gat, 40; Almog Sarusi, 27; and Hersh Goldberg-Polin, the U.S. citizen, 23.

We have met Hersh’s parents, Jon Polin and Rachel Goldberg, and were struck by their strength and good courage, willing to do anything and go anywhere to help their son. The crime here is all on Hamas, which took the innocent hostages on Oct. 7 and has refused to release them through multiple rounds of U.S.-brokered negotiations.

Yet the reaction from the White House, the British government, the Western press and some parts of Israel is to blame the Israeli government. On Monday, in a one-word answer to a press scrum, Mr. Biden accused Prime Minister Benjamin Netanyahu of not doing enough to secure a hostage deal.

Britain’s new Labour government chose Monday to announce that, after a review, it is suspending 30 arms export licenses to Israel. The titular explanation is that there is a “risk” the arms might be used in violation of humanitarian laws against Palestinians. Does the Keir Starmer government mean violations like Hamas shooting innocents in the head? Or does it fear that Jeremy Corbyn, the anti-Israel MP, is forming a group of independent “pro-Gaza” Members? The timing here compounds the bad policy.

Like Qaid Farhan Al-Qadi, the Muslim hostage Israel rescued last week, the murdered six were found in Rafah, the city the world worked so hard to prevent Israel from entering. President Biden’s opposition kept Israel out of Rafah for three months. Vice President Kamala Harris claimed a Rafah invasion would doom its civilians. “I have studied the maps. There’s nowhere for those folks to go,” she said. Israel proved her wrong, evacuating a million Gazans in two weeks. Israel has dismantled Hamas’s Rafah brigade with notably low civilian casualties.

Aid groups hyped worst-case scenarios for a Rafah invasion. Mr. Biden and Ms. Harris withheld weapons to stop Israel from fighting there. Ms. Harris wouldn’t rule out “consequences” if Israel went ahead. Egypt threatened to abrogate its peace treaty with Israel over it. Israel has since found over a dozen tunnels from Rafah into Egypt, which insists that Israel leave the border to let Hamas’s arms smuggling resume. It should be clear now why Israel couldn’t let Hamas rule Rafah.

Mr. Biden said Sunday that “Hamas leaders will pay for these crimes.” But his next sentence pushed for a cease-fire to end the war. Ms. Harris says, “Hamas cannot control Gaza,” an important line that has been missing from her speeches, but that also seems at odds with her insistence on an “immediate cease-fire.”

In executing hostages, Hamas must have figured it would increase pressure on Mr. Netanyahu. Many Israelis demand he make more concessions toward a deal because Hamas has rejected the past several, including the U.S. proposals, which Mr. Netanyahu accepted. Israel’s largest trade union held a brief strike on Monday to demand a deal. Others call that giving in to terrorism; the right-of-center group of hostage families is now demanding the end of negotiations and more military pressure on Hamas.

The choices are heavy, and Israel’s leaders don’t need U.S. pressure driven by an American election calendar. Americans know right from wrong. When Mr. Polin and Ms. Goldberg spoke at the Democratic convention, the crowd chanted “bring them home.” That was also the chant at the Republican convention during the speech by the parents of Omer Neutra, a 22-year-old U.S. hostage still in Gaza.

Israel is offering unprecedented strategic concessions and risking its soldiers’ lives to free hostages. U.S. pressure should be on Hamas, which took the hostages and murders them.

This editorial was published Sept. 3 in The Wall Street Journal.