Israeli Prime Minister Benjamin Netanyahu attends a weekly cabinet meeting in Jerusalem on May 31. (Dan Bality / Pool/European Pressphoto Agency)

ISRAELI PRIME Minister Benjamin Netanyahu faces what looks to him like a serious diplomatic threat: that Western powers, including the United States, will soon launch a multilateral effort to formulate a plan for Palestinian statehood. France is convening a meeting of foreign ministers this week to discuss a possible Middle East peace conference. President Obama is said to be weighing whether to support a U.N. Security Council resolution later this year spelling out terms for a two-state solution. Israel has long opposed any such international initiative, worrying that it would produce results it found unacceptable.

Several months ago, Mr. Netanyahu embarked on a political project that looked as though it could head off the outside intervention. The result, after several twists and turns, has been to make it more likely. Mr. Netanyahu tried to strengthen and moderate his fragile right-wing coalition by striking a deal with the leader of the left-wing Labor Party; as part of the bargain, his government would have stopped supporting settlement expansion in most of the West Bank and embraced an Egyptian offer to broker talks with the Palestinians.

Then the prime minister abruptly switched course. Talks with Labor were suspended, and on Monday, the parliament ratified his appointment of Avigdor Lieberman, a hard-line nationalist with an abysmal international reputation, as defense minister. Mr. Lieberman’s party will join the government coalition, while Labor will remain in the opposition. Its leader, Isaac Herzog, bitterly accused Mr. Netanyahu of losing his nerve “at the moment of truth.”

That may not be entirely fair. Mr. Herzog ran into considerable opposition to the proposed merger from his own party, and Mr. Netanyahu faced a rebellion from the right. As David Makovsky and Dennis Ross of the Washington Institute for Near East Policy observed, the episode served to demonstrate “how deeply polarized Israel has become.”

Israeli officials argue that the new coalition is more flexible on a Palestinian state and that Mr. Netanyahu is still interested in bringing Mr. Herzog into the government. But negative international reaction has been as swift as it was predictable. Mr. Lieberman is well-known for belligerent rhetoric and radical proposals. He recently clashed with military leaders after they prosecuted a soldier who shot dead a wounded and disarmed Palestinian militant. The defense minister he pushed out, Moshe Yaalon, said in departing that “extremist and dangerous forces have taken over Israel.”

In what looked like an effort to mitigate the diplomatic damage, both Mr. Netanyahu and Mr. Lieberman made statements this week in support of a Palestinian state. They hinted that they were interested in reviving the 2002 Arab Peace Initiative, under which dozens of Arab and Muslim countries pledged to establish full diplomatic relations with Israel if it struck a comprehensive peace settlement with the Palestinians.

Such rhetorical gestures are unlikely to reduce the international pressure unless accompanied by actions. Mr. Netanyahu may protest, with some reason, that Palestinian leaders have been uncompromising. But to stop the “internationalization” of the peace process, his government will have to show that it is willing to facilitate rather than foreclose a future Palestinian state. The partial settlement freeze Mr. Netanyahu discussed with Mr. Herzog would be a good start.