There has already been a lot of theorizing about why a little-known Republican businessman, Bob Turner, won Tuesday’s special Congressional election in a traditionally Democratic New York City district. The grim economy appears to have been a big factor in his victory over Assemblyman David Weprin, and some voters also complained about Mr. Weprin’s principled vote in Albany to legalize gay marriage, which was anathema to many ultra-Orthodox Jewish voters.

Some analysts — and eager Republican critics — are also claiming it was a repudiation of President Obama’s policies toward Israel. On Wednesday, an article on the Web site of the Israeli newspaper Haaretz said that “in politics it is the perception that counts,” and that the Democratic loss “will be portrayed, as the outspoken former Mayor Ed Koch put it, ‘as a message to President Obama that he cannot throw Israel under a bus with impunity.’ ”

Mr. Obama has done nothing of the sort; his support for Israel has never wavered. But we fear that Benjamin Netanyahu, the Israeli prime minister, will read the election as yet another reason to ignore the president’s advice and refuse to make any compromises with the Palestinians, no matter how essential for Israel’s own security.

Mr. Koch played a cynical game in urging special-election voters to choose the Republican as a rebuke to Mr. Obama for saying that Israel’s pre-1967 borders — with mutually agreed land swaps — should be the basis of any peace agreement. That has been the basis of every deal sought by American presidents for more than a decade. Mr. Netanyahu now hints that he, too, accepts it.

Mr. Obama has not handled the Israeli-Palestinian issue adroitly. Palestinians certainly waited too long to begin negotiations, and Arab leaders failed to offer initiatives that might give Israel confidence that a serious deal was possible. But Mr. Netanyahu has been the most intractable, building settlements and blaming his inability to be more forthcoming on his conservative coalition. Egged on by Congressional Republicans, he has sought to embarrass Mr. Obama — astonishing behavior for so close an ally that does not serve his own country’s interest.

Mr. Obama has repeatedly affirmed support for Israel and backed it up with action. He has had far more success than President George W. Bush in rallying tough sanctions on Iran. Security cooperation is strong, including accelerated development and funding for an Israeli missile defense system. The administration pressured Egypt last weekend to protect Israel’s diplomats in Cairo, and it negotiated an agreement to ease tensions with Turkey over the Gaza aid flotilla, until Israel pulled out of the deal.

Now, Mr. Obama is risking American ties with a fast-changing Arab world by vowing to veto the Palestinians’ statehood bid at the United Nations. The president supports a two-state solution but rightly believes that can be achieved only through negotiations.

His diplomats are working with allies to persuade the Palestinians that a United Nations vote would be costly for them too, once the euphoria fades in the West Bank and it is clear that little has changed. They are hoping to restart negotiations by defining the main elements of an agreement that guarantees Israel’s security and provides the Palestinians with a viable state. They should put a map and a timeline on the table and demand that both sides join in.

Mr. Netanyahu should be worried that his country is more isolated now than when he took office. That isolation will deepen so long as negotiations remain stalemated. No vote in New York City makes that any less true — or any less dangerous for Israel.