Making peace between Israelis and Palestinians is somewhat like solving a Rubik’s Cube. You get one colored square lined up but the next one just won’t fall into place. So it is now. After three months of American-mediated proximity talks, Prime Minister Benjamin Netanyahu of Israel has agreed to direct negotiations on a two-state solution; the Palestinian president, Mahmoud Abbas, is stubbornly resisting. It is time for him to talk.

There are understandable reasons for Mr. Abbas’s reluctance. We also don’t know whether Mr. Netanyahu, a master manipulator, really wants a deal or whether his hard-line governing coalition would ever let him make one. The proximity talks — the American envoy, George Mitchell, is shuttling again this week between Jerusalem and Ramallah — don’t seem to be getting very far, although there were hints of movement on Tuesday.

Mr. Abbas also is wary of Washington. After Mr. Obama demanded in 2009 that Mr. Netanyahu halt all settlement construction as a prelude to negotiations, Mr. Abbas did the same.

When Mr. Netanyahu forced Mr. Obama to back down and the Israeli leader implemented a more limited and temporary building halt, Mr. Abbas was left clinging to the maximalist position. There are compelling reasons for Mr. Abbas to act, too.

First, Mr. Obama correctly sees a peace deal as a factor in wider regional stability. He invested lots of political capital in a justified but poorly executed attempt to push the Palestinian position by playing hardball with Israel on settlements.

It caused tensions with Mr. Netanyahu and with American Jews. He is pressing hard for direct talks and aides say he is losing patience with Mr. Abbas. It would be foolish for the Palestinian leader to alienate an American president who is committed to playing a more balanced role in negotiations.

Second, Mr. Abbas has the backing of the Arab League, including crucial states like Saudi Arabia and Egypt. Last month, the group formally gave him a green light — important political cover — to enter direct talks. They need to press Mr. Abbas to move now. They should be prepared to increase aid to the Palestinian government and take steps, like opening trade offices, that will boost Israel’s confidence in a peace agreement.

Finally, Mr. Netanyahu’s moratorium on settlement construction expires on Sept. 26. If direct talks are under way, he should have no excuse to resume building. If there are no talks, Mr. Abbas will give him an escape hatch.

Mr. Abbas no doubt is worried that the Palestinians will be blamed if negotiations fail and that Mr. Netanyahu will use the process to give the illusion of progress while never addressing Palestinian concerns about borders, security, refugees and the future of Jerusalem. Mr. Obama must be ready to point fingers when needed and put forward his own proposals if progress lags.

The constant worry is that direct talks will devolve into recriminations and new violence. But if Mr. Abbas is not at the table, there is no serious way of testing Mr. Netanyahu’s intentions and whether there is any real chance of peacefully achieving a Palestinian state. That is the prize Mr. Abbas may be able deliver and his rejectionist rivals — Hamas — cannot. Mr. Abbas, who has long advocated a negotiated two-state solution, is seriously wrong if he thinks his leverage — and the future of the Palestinians — is in staying on the sidelines.