The question is whether the incumbent will choose, or perhaps be obliged by the electoral math, to include parties from the center and left in his coalition. If he does not, Mr. Netanyahu could find himself isolated both within his own government and internationally: He is one of only two of the top 30 candidates from his own Likud Party to endorse Palestinian statehood.

For that reason, the wise U.S. policy would be to concede, and maybe even welcome, Mr. Netanyahu’s reelection while quietly urging him to construct a centrist government. In the coming months Israel and the United States will likely have an urgent need to communicate clearly and cooperate closely on the threat of Iran’s nuclear program; and they must try to preserve the prospect of Palestinian statehood. Mr. Obama and Mr. Netanyahu may be political foils, but as each begins a new term their deeper interest lies in a reset of their relationship.