Yes, Mr. Netanyahu would face strident opposition from within his Likud party, but he could lean on the support of the Israeli center and left to ensure a Knesset majority. And because a referendum on Palestinian statehood would likely receive overwhelming support in Gaza as well as the West Bank, Hamas  always attuned to Palestinian public opinion  would have a hard time standing in the way.

Fourth, there isn’t a lot to negotiate. In the 17 years since the Oslo accords were signed, detailed final status negotiations have dealt exhaustively with all the critical issues. If an independent Palestinian state is to be established, the zone of agreement is clear and the necessary trade-offs are already known.

Security arrangements were all but settled in 2000 at Camp David before the talks collapsed. The increased threat of rocket attacks since then, among other developments, require the two sides to agree on stricter border controls and a robust third-party force in the Jordan Valley. But one year is ample time to resolve this. In fact, if the leaders are sincere in their intent to make a deal, dragging out the negotiations would only weaken them politically and give time for the opponents of peace to rally.

In short, the negotiating environment is better suited to peacemaking today than it has been at any point in the last decade. The prospects for peace depend now on the willpower of the leaders.

Does President Abbas, already a weakened figure, have the courage to defend the necessary concessions to his people, particularly when it comes to conceding the “right of return” to Israel? Does Prime Minister Netanyahu have the determination to withdraw from at least 95 percent of the West Bank and to accept a Palestinian capital in Arab East Jerusalem? And does President Obama have the statesmanship to persuade both parties to make the deal and to reassure them that the United States will be there with a safety net if it fails?

At the end of the Clinton administration, Shimon Peres observed that “history is like a horse that gallops past your window and the true test of statesmanship is to jump from that window onto the horse.” Arafat failed that test, leaving Palestinians and Israelis mired in conflict. We cannot know whether Mr. Abbas and Mr. Netanyahu will take the politically perilous leap. But for the time being, we should suspend disbelief and welcome the fact that American diplomacy has ensured they will soon be put to the test.