THE ON-AGAIN, off-again “unity” agreement between rival Palestinian movements Hamas and Fatah seems to be on again. Or at least it was on Monday, when Palestinian President and Fatah leader Mahmoud Abbas announced a new accord with Hamas chief Khaled Meshal after a meeting in Doha, Qatar. The pact calls for Mr. Abbas to serve as prime minister of a coalition government, which would serve only long enough to hold elections for a new Palestinian leadership. That’s if it gets off the ground: On Wednesday, Hamas’s Gaza-based leadership issued a statement objecting to the deal.

If it does go forward, the Palestinian reconciliation will produce mostly negative results, at least in the short term. Since Hamas has not accepted international demands that it recognize Israel, renounce violence and accept previous international agreements, a unity government will kill what remains of the Israeli-Palestinian “peace process” — including informal talks that have been underway in Amman, Jordan. It probably will lead Israel to suspend delivery of the Palestinian tax revenue it collects and prompt Congress to cut off remaining U.S. aid to the Palestinian Authority. The economic and security progress that average Palestinians have experienced in the past several years, especially in the West Bank, could be halted and possibly reversed.

This prospect is the product of the poor judgment of Mr. Abbas, who chose a year ago to turn his back on diplomacy with Israel and the United States and instead pursue statehood recognition at the United Nations along with Palestinian unity. The U.N. campaign has been a flop, having failed to produce even a Security Council vote. Mr. Abbas now stands to make Palestinian reconciliation — in theory, a desirable prospect — a net loser by refusing to insist that Hamas first renounce violence.

If there is a silver lining here, it is the signs that Hamas itself is reconsidering its place in the Middle East, if not its doctrine, as a result of the uprisings in Egypt and Syria. The latter has effectively broken Hamas’s alliance with the regime of Syrian President Bashar al-Assad and forced Mr. Meshal and other members of its leadership to abandon their headquarters in Damascus. Without the Assad regime, Iran, which has financed and armed Hamas, may soon lack the means to do so. Egypt’s elections, meanwhile, have empowered the Muslim Brotherhood, the organization that gave birth to Hamas — and which long ago gave up violence.

Some Palestinian analysts speculate that Hamas is headed toward embracing the patronage — and the nonviolent Islamist political model — of the Brotherhood or Turkey’s Justice and Development Party. Others point to a possible split between Mr. Meshal and Gaza-based leaders over that issue as well as over the unity accord. In December, Gaza leader Ismail Haniyeh delivered a speech rejecting a shift to nonviolence, saying, “Armed resistance and armed struggle are the strategic way to liberate the Palestinian land from the [Mediterranean] sea to the [Jordan] river.”

As long as that is Hamas’s doctrine, Palestinian unity will do more harm than good. Those who seek Middle East peace must hope that if the ­Abbas-Meshal accord goes forward, it will trigger an Arab Spring for Hamas.