This is a decisive moment. Under the auspices of the Egyptian government, Palestine’s two major political movements — Fatah and Hamas — are signing a reconciliation agreement on Wednesday that will permit both to contest elections for the presidency and legislature within a year. If the United States and the international community support this effort, they can help Palestinian democracy and establish the basis for a unified Palestinian state in the West Bank and Gaza that can make a secure peace with Israel. If they remain aloof or undermine the agreement, the situation in the occupied Palestinian territory may deteriorate with a new round of violence against Israel. Support for the interim government is critical, and the United States needs to take the lead.

This accord should be viewed as a Palestinian contribution to the “Arab awakening,” as well as a deep wish to heal internal divisions. Both sides understand that their goal of an independent Palestinian state cannot be achieved if they remain divided. The agreement also signals the growing importance of an emerging Egyptian democracy. Acting as an honest broker, the interim Egyptian government coaxed both sides to agreement by merging the October 2009 Cairo Accord that Fatah signed with additions that respond to Hamas’s reservations.

The accord commits both sides to consensus appointments of an election commission and electoral court. I have observed three elections in the Palestinian territory, and these institutions have already administered elections that all international observers found to be free, fair, honest and free of violence.

The two parties also pledge to appoint a unity government of technocrats — i.e., neither Fatah nor Hamas. Security will be overseen by a committee set up by Palestinian President Mahmoud Abbas (Abu Mazen), and Egypt will assist.

Why should the United States and the international community support the agreement? First, it respects Palestinian rights and democracy. In 2006, Hamas won the legislative election, but the “Quartet” — the United States, the European Union, the United Nations and Russia — rejected it and withheld aid, and the unity government collapsed. Competition between the two factions turned vicious, and each side has arrested the other’s activists. Instead of exacerbating differences between the two parties, the international community should help them resolve disagreements through electoral and legislative processes.

Second, with international support, the accord could lead to a durable cease-fire. Israel and the United States are concerned that Hamas could use a unity government to launch attacks against Israel. I have visited the Israeli border town of Sderot and share their concern. I urged Hamas’s leaders to stop launching rockets, and they attempted to negotiate a lasting mutual cease-fire. The United States and other Quartet members should assist Hamas and Israel’s search for a cease-fire.

Third, the accord could be a vehicle to press for a final peace agreement for two states. Abu Mazen will be able to negotiate on behalf of all Palestinians. And with Quartet support, a unity government can negotiate with Israel an exchange of prisoners for the captured Israeli soldier Gilad Shalit and a settlement freeze. In my talks with Hamas leader Khaled Meshal, he said Hamas would accept a two-state agreement that is approved in a Palestinian referendum. Such an agreement could provide mutual recognition — Israel would recognize an independent Palestinian state and Palestine would recognize Israel. In other words, an agreement will include Hamas’s recognition of Israel.

Suspicions of Hamas stem from its charter, which calls for Israel’s destruction. I find the charter repugnant. Yet it is worth remembering that Israel negotiated the Oslo Accords with the Palestine Liberation Organization while its charter had similar provisions. It took five more years before the PLO Charter was altered.

Many Israelis say that as long as the Palestinians are divided, there is no partner for peace. But at the same time, they refuse to accept a unity government. In Cairo this week, the Palestinians are choosing unity. It is a fragile unity, but the Quartet should work with them to make it secure and peaceful enough to jump-start final-status negotiations with Israel.

The writer was the 39th president of the United States. He founded the not-for-profit Carter Center, which seeks to advance peace and health worldwide.