President Donald Trump recently recognized Jerusalem as Israel’s capital and plans to move the U.S. embassy there from Tel Aviv. But Trump didn’t appear to anticipate the resulting political fallout in the Mideast — and even among European allies — so once again a unilateral decision has left America diplomatically isolated.

The decision will embolden Palestinian hard-liners, including Hamas, which Israel, the U.S. and the European Union rightly consider a terrorist group. It also will weaken the more moderate Fatah movement led by Palestinian President Mahmoud Abbas. So the reconciliation between the two factions required for any eventual peace process will be even more difficult to achieve. And in the broader Mideast, the Sunni governments inching toward more cooperation with Israel may have to retrench as they react to calls like the one from the 57-member Organization of Islamic Cooperation, which on Wednesday declared that East Jerusalem was the capital of Palestine.

Perhaps most menacingly, the reactionary factions within the theocracy ruling Iran will be bolstered. “In one respect this was a victory handed by the president to radical elements in Iran,” Daniel Kurtzer, ambassador to Israel during the George W. Bush administration and to Egypt during the Clinton administration, told an editorial writer. “Iran can now advertise as a defender of the Palestinian cause,” Kurtzer said, adding that although that’s not actually the case, “it’s not a rational moment in the Middle East.”

Former Mideast peace envoy Dennis Ross was troubled by another aspect of Trump’s declaration. “You are taking what is the most emotional issue … and you are not preparing the ground,” he said during a conference call. Ross, now a distinguished fellow at the Washington Institute for Near East Policy, supports Trump’s move in principle but faults the execution. Surprise, Ross said, “always drives others into their most defensive position.”

It’s also surprising that Trump apparently didn’t ask, and certainly didn’t get, anything in return for the diplomatic victory he handed to Israeli Prime Minister Benjamin Netanyahu. So a key component of any negotiated settlement between the Israelis and Palestinians was settled with no commensurate concessions from Israel, and it met with near universal disapproval from adversary and ally alike.

The protests may subside, but the enduring damage to U.S. efforts may endure, especially after Abbas said that the Palestinians would no longer accept the U.S. as an honest broker. That would be a loss for the U.S., Israel and the Palestinians, as well as the entire region. No one doubts the enduring U.S.-Israel alliance and that Trump in particular seemed sympathetic to Netanyahu’s political positions. But what may initially appear to be a diplomatic gift may not be the kind of friendship Israel really needs. Because the most important objective for Israel shouldn’t be an embassy location but two states peacefully coexisting.